Professor Joseph Keddie

Professor of Soft Matter Physics

Qualifications: BA, BS (Alfred, USA); MS, PhD (Cornell, USA), CPhys, FInstP, MIM

Email:
Phone: Work: 01483 68 6803
Room no: 04 BB 03

Further information

Biography

Joe Keddie is Professor of Soft Matter Physics within the Soft Matter Physics Group.

After graduating from Cornell University (USA), Joe Keddie spent two years as a post-doctoral researcher in the Polymer & Colloids Group at the Cavendish Laboratory, Cambridge followed by one year as an Oppenheimer Fellow. At Cambridge he used ellipsometry and environmental-SEM to study polymer colloids and thin films. In 1995 Joe moved to the University of Surrey as a Foundation Fund lecturer. Throughout his time at Surrey he has carried out research on soft matter, with special interest in polymer colloids. In recognition of his contributions to the understanding of polymer dynamics of polymers in thin films and colloidal dispersions, he was awarded the 2001 Paterson Medal and Prize by the Institute of Physics and named a Fellow. His research group won two Roon Awards from the Federation of Societies for Coatings Technology for papers presented at their Annual Meeting. In 2006 he was inducted into the Phi Beta Kappa honor society by his alma mater, Alfred University. A co-author of >100 journal articles and book chapters, he also holds two US patents and has recently submitted two international patent applications.  He has recently written - along with his co-author, Alex Routh, at the University of Cambridge - a book entitled Fundamentals of Latex Film Formation:  Processes and Properties.  This book was published in 2010 by Springer. In September 2011, he was elected the chair of the Institute of Physics Polymer Physics Group.

Research Interests

Professor Keddie is interested in fundamental processes in soft matter, especially polymer thin films, nanoparticles, and colloidal dispersions. Follow this link to see the active research topics of the Soft Matter Physics Group. Particular topics of recent research are

Along with others in the Soft Condensed Matter group, he uses several non-invasive probes, including atomic force microscopy, ellipsometry (both visible and IR), ion beam analysis and magnetic resonance profiling. He has particular expertise in the mechanisms by which polymer colloids form films and published a book on that topic in 2010.

Research Collaborations

Joe Keddie is currently collaborating with several European paint manufacturers and the University of Lyon in an FP7 project, called BARRIER-PLUS, which is developing new waterborne, nanocomposite coatings as barriers against corrosion.  He was previously a leader in two European projects (NsHAPe and NAPOLEON) concerning the development of improved waterborne, polymer coatings and adhesives through the control of their structure on the nanoscale. The NAPOLEON project has 21 partners, including nine from industry. He collaborates with Richard Sear and Alan Dalton in research on crystallisation and carbon nanotube/polymer composites. With Paul Sellin, he is developing the use of conjugated polymers for radiation detectors. A large fraction of his research has been supported by industries, including Cytec Specialty Chemicals (Drogenbos, Belgium), Akzo Nobel (Slough and Wilton), International Paint (Felling), BASF (Germany), Sun Chemicals (Orpington) and Dow Corning (Barry, South Wales). In recent projects, Joe has collaborated with Prof. Brian Vincent (Bristol), Costantino Creton (ESPCI, Paris), Prof. Jose' Asua (Univ. of the Basque Country, Spain),  Diethelm Johannsmann (Clausthal University of Technology), Prof. Ken Shull (Northwestern Univ.), Prof. Steve Armes (University of Sheffield), and Prof. Jian Lu (now at Manchester).

Publications

Highlights

  • Georgiadis A, Routh AF, Murray MW, Keddie JL. (2011) 'Bespoke periodic topography in hard polymer films by infrared radiation-assisted evaporative lithography'. ROYAL SOCIETY OF CHEMISTRY Soft Matter, 7 (23), pp. 11098-11102.
  • Worajittiphon P, Jurewicz I, King AAK, Keddie JL, Dalton AB. (2010) 'Enhanced Thermal Actuation in Thin Polymer Films Through Particle Nano-Squeezing by Carbon Nanotube Belts'. WILEY-V C H VERLAG GMBH ADVANCED MATERIALS, 22 (46), pp. 5310-5314.
  • Liu D, Wang T, Keddie JL. (2009) 'Protein Nanopatterning on Self-Organized Poly(styrene-b-isoprene) Thin Film Templates'. American Chemical Society LANGMUIR, 25 (8), pp. 4526-4534.

    Abstract

    Templated surfaces can be used to create patterns of proteins for applications in cell biology, biosensors, and tissue engineering. A diblock copolymer template, which contains a pair of hydrophobic blocks, has been developed. The template is created from well-ordered, nonequilibrium surface structures of poly(styrene-b-isoprene) (PS-b-PI) diblock copolymers, which are achieved in ultrathin films having a thickness of less than one domain period. Adsorption and nanopatterning of bovine serum albumin (BSA) on these thin films were studied. After incubation of the copolymer templates in BSA solutions (500 μg/mL) for a period of 1 h, BSA molecules formed either a striped or a dense, ringlike structure, closely resembling the underlying polymer templates. In this “hard-soft” PS-b-PI system, BSA molecules were preferentially adsorbed on the hard PS domains, rather than on the soft PI domains. Secondary ion mass spectroscopy (SIMS) and contact angle analysis revealed that, with more PI localized at the free surface, fewer BSA molecules were adsorbed. SIMS analysis confirmed that BSA molecules were adsorbed selectively on the PS blocks. This is the first example of two hydrophobic blocks of a diblock copolymer being used as a protein patterning template. Previously reported diblock copolymer templates used hydrophilic and hydrophobic pairs. A potentially useful characteristic of this template is that it is effective at high protein solution concentrations (up to 1 mg/mL) and for long incubation times (up to 2 h), which broadens its range of applicability in various uses.

  • Wang T, Colver PJ, Bon SAF, Keddie JL. (2009) 'Soft polymer and nano-clay supracolloidal particles in adhesives: synergistic effects on mechanical properties'. ROYAL SOC CHEMISTRY SOFT MATTER, 5 (20), pp. 3842-3849.
  • Deplace F, Rabjohns MA, Yamaguchi T, Foster AB, Carelli C, Lei C-H, Ouzineb K, Keddie JL, Lovell PA, Creton C. (2009) 'Deformation and adhesion of a periodic soft-soft nanocomposite designed with structured polymer colloid particles'. ROYAL SOC CHEMISTRY SOFT MATTER, 5 (7), pp. 1440-1447.
  • Wang T, Dalton AB, Keddie JL. (2008) 'Importance of Molecular Friction in a Soft Polymer-Nanotube Nanocomposite'. AMER CHEMICAL SOC MACROMOLECULES, 41 (20), pp. 7656-7661.
  • Wang T, Lei C-H, Liu D, Manea M, Asua JM, Creton C, Dalton AB, Keddie JL. (2008) 'A molecular mechanism for toughening and strengthening waterborne nanocomposites'. WILEY-V C H VERLAG GMBH ADVANCED MATERIALS, 20 (1), pp. 90-+.

Journal articles

  • Georgiadis A, Muhamad FN, Utgenannt A, Keddie JL. (2013) 'Aesthetically textured, hard latex coatings by fast IR-assisted evaporative lithography'. Progress in Organic Coatings, 76 (12), pp. 1786-1791.
  • Akram N, Ishaq M, Zuber M, Gurney RS, Keddie JL. (2013) 'Influence of Polyol Molecular Weight and Type on the Tack and Peel Properties of Waterborne Polyurethane Pressure-Sensitive Adhesives'. Macromolecular Reaction Engineering, 7 (10), pp. 493-503.
  • Mills CA, Al-Otaibi H, Intaniwet A, Shkunov M, Pani S, Keddie JL, Sellin PJ. (2013) 'Enhanced x-ray detection sensitivity in semiconducting polymer diodes containing metallic nanoparticles'. Institute of Physics Journal of Physics D: Applied Physics, 46 (27) Article number 275102

    Abstract

    Semiconducting polymer X-radiation detectors are a completely new family of low-cost radiation detectors with potential application as beam monitors or dosimeters. These detectors are easy to process, mechanically flexible, relatively inexpensive, and able to cover large areas. However, their x-ray photocurrents are typically low as, being composed of elements of low atomic number (Z), they attenuate x-rays weakly. Here, the addition of high-Z nanoparticles is used to increase the x-ray attenuation without sacrificing the attractive properties of the host polymer. Two types of nanoparticles (NPs) are compared: metallic tantalum and electrically insulating bismuth oxide. The detection sensitivity of 5 µm thick semiconducting poly([9,9-dioctylfluorenyl-2,7-diyl]-co-bithiophene) diodes containing tantalum NPs is four times greater than that for the analogous NP-free devices; it is approximately double that of diodes containing an equal volume of bismuth oxide NPs. The x-ray induced photocurrent output of the diodes increases with an increased concentration of NPs. However, contrary to the results of theoretical x-ray attenuation calculations, the experimental current output is higher for the lower-Z tantalum diodes than the bismuth oxide diodes, at the same concentration of NP loading. This result is likely due to the higher tantalum NP electrical conductivity, which increases charge transport through the semiconducting polymer, leading to increased diode conductivity.

  • Mills CA, Chan Y-F, Intaniwet A, Nisbet A, Keddie JL, Sellin PJ. (2013) 'Direct Detection of 6 MV X-rays from a Medical Linear Accelerator using a Semiconducting Polymer Diode'. Institute of Physics Physics in Medicine and Biology, 58 (13), pp. 4471-4482.
  • Utgenannt A, Muskens OL, Kanaras AG, Keddie JL. (2013) 'Directed organization of gold nanoparticles in polymer coatings through infrared-assisted evaporative lithography'. Chemical Communications, 49 (39), pp. 4253-4255.
  • Gurney RS, Dupin D, Siband E, Ouzineb K, Keddie JL. (2013) 'Large-area patterning of the tackiness of a nanocomposite adhesive by sintering of nanoparticles under IR radiation.'. ACS Appl Mater Interfaces, United States: 5 (6), pp. 2137-2145.

    Abstract

    We present a simple technique to switch off the tack adhesion in selected areas of a colloidal nanocomposite adhesive. It is made from a blend of soft colloidal polymer particles and hard copolymer nanoparticles. In regions that are exposed to IR radiation, the nanoparticles sinter together to form a percolating skeleton, which hardens and stiffens the adhesive. The tack adhesion is lost locally. Masks can be made from silicone-coated disks, such as coins. Under the masks, adhesive island regions are defined with the surrounding regions being a nontacky coating. When optimizing the nanocomposite's adhesive properties, the addition of the hard nanoparticles raises the elastic modulus of the adhesive significantly, but adhesion is not lost because the yield point remains relatively low. During probe-tack testing, the soft polymer phases yield and enable fibrillation. After heating under IR radiation, the storage modulus increases by a factor of 5, and the yield point increases nearly by a factor of 6, such that yielding and fibrillation do not occur in the probe-tack testing. Hence, the adhesion is lost. Loading and unloading experiments indicate that a rigid skeleton is created when the nanoparticles sinter together, and it fractures under moderate strains. This patterning method is relatively simple and fast to execute. It is widely applicable to other blends of thermoplastic hard nanoparticles and larger soft particles.

  • Gonzalez E, Paulis M, Barandiaran MJ, Keddie JL. (2013) 'Use of a Routh-Russel deformation map to achieve film formation of a latex with a high glass transition temperature'. Langmuir, 29 (6), pp. 2044-2053.

    Abstract

    In the film formation of latex, particle deformation can occur by processes of wet sintering, dry sintering, or capillary action. When latex films dry nonuniformly and when particles deform and coalesce while the film is still wet, a detrimental skin layer will develop at the film surface. In their process model, Routh and Russel proposed that the operative particle deformation mechanism can be determined by the values of control parameters on a deformation map. Here, the film formation processes of three methyl methacrylate/butyl acrylate copolymer latexes with high glass transition temperatures (T ), ranging from 45 to 64 C, have been studied when heated by infrared radiation. Adjusting the infrared (IR) power density enables the film temperature, polymer viscosity, and evaporation rate during latex film formation to be controlled precisely. Different polymer particle deformation mechanisms have been demonstrated for the same latex under a variety of film formation process conditions. When the temperature is too high, a skin layer develops. On the other hand, when the temperature is too low, particles deform by dry sintering, and the process requires extended time periods. The deduced mechanisms can be interpreted and explained by the Routh-Russel deformation maps. Film formation of hard (high T) coatings is achieved without using coalescing aids that emit volatile organic compounds (VOCs), which is a significant technical achievement. © 2013 American Chemical Society.

  • Georgiadis A, Muhamad FN, Utgenannt A, Keddie JL. (2013) 'Aesthetically textured, hard latex coatings by fast IR-assisted evaporative lithography'. Progress in Organic Coatings,

    Abstract

    Polymer coatings with periodic topographic patterns, repeating over millimetre length scales, can be created from lateral flows in an aqueous dispersion of colloidal particles. The flow is driven by differences in evaporation rate across the wet film surface created by IR radiative heating through a shadow mask. This new process, which we call IR radiation-assisted evaporative lithography (IRAEL), combines IR particle sintering with the concept of evaporative lithography. Here, a series of experiments has been conducted in which the mass of the latex is measured as a function of the exposure time under infrared radiation through a mask. The water evaporation rates and the minimum exposure time required for a dry film are estimated as a function of the power density of the IR emitter. The temperature of the wet film is monitored to avoid overheating and boiling of the water, which will otherwise cause defects. It is demonstrated that textured films can be created on a variety of substrates (plastics, metals, paper and glass), and processing times can be as short as 5 min. We use IRAEL to decorate household goods with an aesthetic coating with the desired texture. © 2013 Elsevier B.V. All rights reserved.

  • Lopez A, Reyes Y, Asua JM, Lopez A, Degrandi-Contraires E, Creton C, Canetta E, Keddie JL, Canetta E. (2013) 'Simultaneous free-radical and addition miniemulsion polymerization: Effect of the chain transfer agent on the microstructure of polyurethane-acrylic pressure-sensitive adhesives'. Wiley-VCH Verlag Berlin Macromolecular Materials and Engineering, 298 (1), pp. 53-66.
  • Gurney RS, Dupin D, Nunes JS, Ouzineb K, Siband E, Asua JM, Armes SP, Keddie JL. (2012) 'Switching Off the Tackiness of a Nanocomposite Adhesive in 30 s via Infrared Sintering.'. American Chemical Society ACS Appl Mater Interfaces, United States: 4 (10), pp. 5442-5452.

    Abstract

    Soft adhesives require an optimum balance of viscous and elastic properties. Adhesion is poor when the material is either too solidlike or too liquidlike. The ability to switch tack adhesion off at a desired time has many applications, such as in recycling, disassembly of electronics, and painless removal of wound dressings. Here, we describe a new strategy to switch off the tack adhesion in a model nanocomposite adhesive in which temperature is the trigger. The nanocomposite comprises hard methacrylic nanoparticles blended with a colloidal dispersion of soft copolymer particles. At relatively low volume fractions, the nanoparticles (50 nm diameter) accumulate near the film surface, where they pack around the larger soft particles (270 nm). The viscoelasticity of the nanocomposite is adjusted via the nanoparticle concentration. When the nanocomposite is heated above the glass transition temperature of the nanoparticles (T(g) = 130 °C), they sinter together to create a rigid network that raises the elastic modulus at room temperature. The tackiness is switched off. Intense infrared radiation is used to heat the nanocomposites, leading to a fast temperature rise. Tack adhesion is switched off within 30 s in optimized compositions. These one-way switchable adhesives have the potential to be patterned through localized heating.

  • Jurewicz I, Keddie JL, Dalton AB. (2012) 'Importance of capillary forces in the assembly of carbon nanotubes in a polymer colloid lattice.'. American Chemical Society Langmuir, United States: 28 (21), pp. 8266-8274.

    Abstract

    We highlight the significance of capillary pressure in the directed assembly of nanorods in ordered arrays of colloidal particles. Specifically, we discuss mechanisms for the assembly of carbon nanotubes at the interstitial sites between latex polymer particles during composite film formation. Our study points to general design rules to be considered to optimize the ordering of nanostructures within such polymer matrices. In particular, gaining an understanding of the role of capillary forces is critical. Using a combination of electron microscopy and atomic force microscopy, we show that the capillary forces acting on the latex particles during the drying process are sufficient to bend carbon nanotubes. The extent of bending depends on the flexural rigidity of the carbon nanotubes and whether or not they are present as bundled ensembles. We also show that in order to achieve long-range ordering of the nanotubes templated by the polymer matrix, it is necessary for the polymer to be sufficiently mobile to ensure that the nanotubes are frozen into the ordered network when the film is formed and the capillary forces are no longer dominant. In our system, the polymer is plasticized by the addition of surfactant, so that it is sufficiently mobile at room temperature. Interestingly, the carbon nanotubes effectively act as localized pressure sensors, and as such, the study agrees well with previous theoretical predictions calculating the magnitude of capillary forces during latex film formation.

  • Trueman RE, Lago Domingues E, Emmett SN, Murray MW, Keddie JL, Routh AF. (2012) 'Autostratification in drying colloidal dispersions: experimental investigations'. American Chemical Society Langmuir, United States: 28 (7), pp. 3420-3428.

    Abstract

    In films cast from a colloidal dispersion comprising two particle sizes, we experimentally examine the distribution of particles normal to the substrate. The particle concentrations at various positions in the film are determined through atomic force microscopy and NMR profiling. The results are compared to a previously derived diffusional model. Evidence for diffusional driven stratification is found, but the importance of other flows is also highlighted. The conditions that enhance particle stratification are found to be a colloidally stable dispersion, low initial volume fractions, a low concentration of the stratifying particle, and for the Peclet numbers of the two components to straddle unity.

  • Irmukhametova GS, Fraser BJ, Keddie JL, Mun GA, Khutoryanskiy VV. (2012) 'Hydrogen-Bonding-Driven Self-Assembly of PEGylated Organosilica Nanoparticles with Poly(acrylic acid) in Aqueous Solutions and in Layer-by-Layer Deposition at Solid Surfaces'. American Chnemical Society LANGMUIR, 28 (1), pp. 299-306.

    Abstract

    PEGylated organosilica nanoparticles have been synthesized through self-condensation of 3-mercaptopropyltrimethoxysilane in dimethylsulfoxide into thiolated nanoparticles with their subsequent reaction with methoxypolyethylene glycol maleimide. The PEGylated nanoparticles showed excellent colloidal stability over a wide range of pHs in contrast to the parent thiolated nanoparticles, which have a tendency to aggregate irreversibly under acidic conditions (pH < 3.0). Due to the presence of a poly(ethylene glycol)-based corona, the PEGylated nanoparticles are capable of forming hydrogen-bonded interpolymer complexes with poly(acrylic acid) in aqueous solutions under acidic conditions, resulting in larger aggregates. The use of hydrogen-bonding interactions allows their more efficient attachment of the nanoparticles to surfaces. The alternating deposition of PEGylated nanoparticles and poly(acrylic acid) on silicon wafer surfaces in a layer-by-layer fashion leads to multilayered coatings. The self-assembly of PEGylated nanoparticles with poly(acrylic acid) in aqueous solutions and at solid surfaces was compared to the behavior of linear poly(ethylene glycol). The nanoparticle system creates thicker layers than the poly(ethylene glycol), and a thicker layer is obtained on a poly(acrylic acid) surface than on a silica surface, because of the effects of hydrogen bonding. Some implications of these hydrogen bonding-driven interactions between PEGylated nanoparticles and poly(acrylic acid) for pharmaceutical formulations are discussed.

  • Goikoetxea M, Reyes Y, de las Heras Alarcón CM, Minari RJ, Beristain I, Paulis M, Barandiaran MJ, Keddie JL, Asua JM. (2012) 'Transformation of waterborne hybrid polymer particles into films: Morphology development and modeling'. Elsevier Polymer, 53 (5), pp. 1098-1108.

    Abstract

    Films cast from multiphase polymer particles have the potential to combine the properties of their components synergistically. The properties of the film depend on the hybrid polymer architecture and the film morphology. However, how the polymer microstructure and particle morphology are transformed during film formation to determine the film morphology is not well understood. Here, using waterborne alkyd-acrylic nanocomposite particles in a case study, it was found that phase migration leading to the formation of aggregates occurred during film formation. A coarse-grained Monte Carlo model was developed to account for the effects of polymer microstructure and particle morphology on the morphology of the film. The model was validated by comparing its predictions with the observed effects, and then used to explore combinations of polymer microstructure and particle morphology not attainable with the system used as a case study. Significantly, the compatibility of the phases was found to have a greater influence than the morphology of the particles in determining the film structure.

  • Intaniwet A, Mills CA, Shkunov M, Sellin PJ, Keddie JL. (2012) 'Heavy metallic oxide nanoparticles for enhanced sensitivity in semiconducting polymer x-ray detectors'. IOP Publishing Nanotechnology, 23 (23) Article number 235502

    Abstract

    Semiconducting polymers have previously been used as the transduction material in x-ray dosimeters, but these devices have a rather low detection sensitivity because of the low x-ray attenuation efficiency of the organic active layer. Here, we demonstrate a way to overcome this limitation through the introduction of high density nanoparticles having a high atomic number (Z) to increase the x-ray attenuation. Specifically, bismuth oxide (Bi O ) nanoparticles (Z=83 for Bi) are added to a poly(triarylamine) (PTAA) semiconducting polymer in the active layer of an x-ray detector. Scanning electron microscopy (SEM) reveals that the Bi O nanoparticles are reasonably distributed in the PTAA active layer. The reverse bias dc currentvoltage characteristics for PTAABi O diodes (with indium tin oxide (ITO) and Al contacts) have similar leakage currents to ITO/PTAA/Al diodes. Upon irradiation with 17.5keV x-ray beams, a PTAA device containing 60wt% Bi O nanoparticles demonstrates a sensitivity increase of approximately 2.5 times compared to the plain PTAA sensor. These results indicate that the addition of high-Z nanoparticles improves the performance of the dosimeters by increasing the x-ray stopping power of the active volume of the diode. Because the Bi O has a high density, it can be used very efficiently, achieving a high weight fraction with a low volume fraction of nanoparticles. The mechanical flexibility of the polymer is not sacrificed when the inorganic nanoparticles are incorporated. © 2012 IOP Publishing Ltd.

  • Georgiadis A, Routh AF, Murray MW, Keddie JL. (2011) 'Bespoke periodic topography in hard polymer films by infrared radiation-assisted evaporative lithography'. ROYAL SOCIETY OF CHEMISTRY Soft Matter, 7 (23), pp. 11098-11102.
  • Intaniwet A, Keddie JL, Shkunov M, Sellin PJ. (2011) 'High charge-carrier mobilities in blends of poly(triarylamine) and TIPS-pentacene leading to better performing X-ray sensors'. Elsevier Organic Electronics, 12 (11), pp. 1903-1908.

    Abstract

    A new class of X-ray sensor – in which there is a blend of poly(triarylamine) (PTAA) and 6,13-bis(triisopropylsilylethynyl) (TIPS)-pentacene in the active layer of a diode structure – has been developed. The crystalline pentacene provides a fast route for charge carriers and leads to enhanced performance of the sensor. The first time-of-flight charge-carrier mobility measurement of this blend is reported. The mobility of PTAA and TIPS-pentacene in a 1:25 molar ratio was found to be 2.2 × 10−5 cm2 V−1 s−1 (averaged for field strengths between 3 × 104 and 4 × 105 V cm−1), which is about 17 times higher than that obtained in PTAA over the same range of field strengths. This higher mobility is correlated with a fourfold increase in the X-ray detection sensitivity in the PTAA:TIPS-pentacene devices.

  • Jurewicz I, Worajittiphon P, King AA, Sellin PJ, Keddie JL, Dalton AB. (2011) 'Locking carbon nanotubes in confined lattice geometries--a route to low percolation in conducting composites.'. J Phys Chem B, United States: 115 (20), pp. 6395-6400.
  • Lopez A, Degrandi-Contraires E, Canetta E, Creton C, Keddie JL, Asua JM. (2011) 'Waterborne Polyurethane-Acrylic Hybrid Nanoparticles by Miniemulsion Polymerization: Applications in Pressure-Sensitive Adhesives'. AMER CHEMICAL SOC LANGMUIR, 27 (7), pp. 3878-3888.
  • Georgiadis A, Bryant PA, Murray M, Beharrell P, Keddie JL. (2011) 'Resolving the Film-Formation Dilemma with Infrared Radiation-Assisted Sintering.'. American Chemical Society Langmuir, 27 (6), pp. 2176-2180.

    Abstract

    The film formation of an acrylate latex with a glass-transition temperature of 38 °C has been achieved through the use of near-infrared (NIR) radiative heating. A hard, crack-free coating was obtained without the addition of plasticizers. Sintering of acrylate particles was confirmed through measurements using atomic force microscopy. The addition of an NIR-absorbing polymer increased the rate of particle deformation such that it was significantly greater than obtained in a convection oven at 60 °C. The results are consistent with a lower polymer viscosity under infrared radiation, according to a simple analysis using a standard model of sintering.

  • López García I, Keddie JL, Sferrazza M. (2011) 'Some insights into the structural relaxation of spin-cast, glassy polymer thin films'. Nature Publishing Group Polymer Journal, 43 (2), pp. 214-217.

    Abstract

    The widespread use of thin films in a range of applications and industries, from coatings, inks and lithography to nano-imprinting, optoelectronics and memory devices,1 has made the understanding of thin films, particularly the changes induced by structural relaxation and solvent evaporation, very important. There is a need to know whether a film will change in dimensions after its deposition and how fast these changes will occur.

  • Lopez A, Degrandi E, Canetta E, Keddie JL, Creton C, Asua JM. (2011) 'Simultaneous free radical and addition miniemulsion polymerization: Effect of the diol on the microstructure of polyurethane-acrylic pressure-sensitive adhesives'. Elsevier Polymer, 52 (14), pp. 3021-3030.
  • López García I, Keddie JL, Sferrazza M. (2011) 'Probing the early stages of solvent evaporation and relaxation in solvent-cast polymer thin films by spectroscopic ellipsometry'. Wiley Surface and Interface Analysis, 43 (11), pp. 1448-1452.
  • Worajittiphon P, Jurewicz I, King AAK, Keddie JL, Dalton AB. (2010) 'Enhanced Thermal Actuation in Thin Polymer Films Through Particle Nano-Squeezing by Carbon Nanotube Belts'. WILEY-V C H VERLAG GMBH ADVANCED MATERIALS, 22 (46), pp. 5310-5314.
  • Liu D, Abdullah CAC, Sear RP, Keddie JL. (2010) 'Cell adhesion on nanopatterned fibronectin substrates'. ROYAL SOC CHEMISTRY SOFT MATTER, 6 (21), pp. 5408-5416.

    Abstract

    The coating of substrates with an extracellular matrix (ECM) protein, such as fibronectin (FN), is often employed to increase cell adhesion and growth. Here, we examine the influence of the size scale and geometry of novel FN nanopatterns on the adhesion and spreading of Chinese Hamster Ovary (CHO) cells. The FN is patterned on the surface of templates created through the self-assembly of polystyrene-block-polyisoprene (PS-b-PI) diblock copolymers. Both ring-like and stripe-like FN nanopatterns are created through the preferential adsorption of FN on PS blocks, as confirmed through the complementary use of atomic force microscopy and secondary ion mass spectrometry. The ring-like FN nanopattern substrate increases the cells' adhesion compared with the cells on homogeneous FN surfaces and the stripe-like FN nanopatterns. Cell adhesion is high when the FN ring size is greater than 50 nm and when the surface coverage of FN is less than ca. 85%. We suggest that the ring-like nanopatterns of FN may be aiding cell adhesion by increasing the clustering of the proteins (integrins) with which cells bind to the nanopatterned substrate. This clustering is required for cell adhesion. In comparison to lithographic techniques, the FN templating method, presented here, provides a simple, convenient and economical way of coating substrates for tissue cultures and should be applicable to tissue engineering.

  • Wang T, de las Heras Alarcon CD, Goikoetxea M, Beristain I, Paulis M, Barandiaran MS, Asua JM, Keddie JL. (2010) 'Cross-Linked Network Development in Compatibilized Alkyd/Acrylic Hybrid Latex Films for the Creation of Hard Coatings'. American Chemical Society Langmuir: the ACS journal of surfaces and colloids, 26 (17), pp. 14323-14333.
  • Intaniwet A, Mills CA, Sellin PJ, Shkunov M, Keddie JL. (2010) 'Achieving a Stable Time Response in Polymeric Radiation Sensors under Charge Injection by X-rays'. 5th Edition. AMER CHEMICAL SOC ACS APPL MATER INTER, 2 (6), pp. 1692-1699.

    Abstract

    Existing inorganic materials for radiation sensors suffer from several drawbacks, including their inability to cover large curved areas, lack of tissue equivalence toxicity, and mechanical inflexibility. As an alternative to inorganics, poly(triarylamine) (PTAA) diodes have been evaluated for their suitability for detecting radiation via the direct creation of X-ray induced photocurrents. A single layer of PTAA is deposited on indium tin oxide (ITO) substrates, with top electrodes selected from Al, Au, Ni, and Pd. The choice of metal electrode has a pronounced effect on the performance of the device; there is a direct correlation between the diode rectification factor and the metal-PTAA barrier height. A diode with an Al contact shows the highest quality of rectifying junction, and it produces a high X-ray photocurrent (several nA) that is stable during continuous exposure to 50 kV Mo K alpha X-radiation over long time scales, combined with a high signal-to-noise ratio with fast response times of less than 0.25 s. Diodes with a low band gap, 'Ohmic' contact, such as ITO/PTAA/Au, show a slow transient response. This result can be explained by the build-up of space charge at the metal-PTAA interface, caused by a high level of charge injection due to X-ray-induced carriers. These data provide new insights into the optimum selection of metals for Schottky contacts on organic materials, with wider applications in light sensors and photovoltaic devices.

  • Jurewicz I, King AAK, Worajittiphon P, Asanithi P, Brunner EW, Sear RP, Hosea TJC, Keddie JL, Dalton AB. (2010) 'Colloid-Assisted Self-Assembly of Robust, Three-Dimensional Networks of Carbon Nanotubes over Large Areas'. WILEY-V C H VERLAG GMBH MACROMOLECULAR RAPID COMMUNICATIONS, 31 (7), pp. 609-615.
  • Agirre A, Asua JM, Heras-Alarcón CDL, Wang T, Keddie JL. (2010) 'Waterborne, semicrystalline, pressure-sensitive adhesives with temperature-responsiveness and optimum properties'. ACS Applied Materials and Interfaces, 2 (2), pp. 443-451.
  • Bushnak IA, Labeed FH, Sear RP, Keddie JL. (2010) 'Adhesion of microorganisms to bovine submaxillary mucin coatings: effect of coating deposition conditions'. TAYLOR & FRANCIS LTD BIOFOULING, 26 (4), pp. 387-397.

    Abstract

    The adhesion of Staphylococcus epidermidis, Escherichia coli, and Candida albicans on mucin coatings was evaluated to explore the feasibility of using the coating to increase the infection resistance of biomaterials. Coatings of bovine submaxillary mucin (BSM) were deposited on a base layer consisting of a poly(acrylic acid-b-methyl methacrylate) (PAA-b-PMMA) diblock copolymer. This bi-layer system exploits the mucoadhesive interactions of the PAA block to aid the adhesion of mucin to the substratum, whereas the PMMA block prevents dissolution of the coating in aqueous environments. The thickness of the mucin coating was adjusted by varying the pH of the solution from which it was deposited. Thin mucin coatings decreased the numbers of bacteria but increased the numbers of C. albicans adhering to the copolymer and control surfaces. Increasing the mucin film thickness resulted in a further lowering of the density of adhering S. epidermidis cells, but it did not affect the density of E. coli. In contrast, the density of C. albicans increased with an increase in mucin thickness.

  • Agirre A, de las Heras-Alarcon C, Wang T, Keddie JL, Asua JM. (2010) 'Waterborne, Semicrystalline, Pressure-Sensitive Adhesives with Temperature-Responsiveness and Optimum Properties'. AMER CHEMICAL SOC ACS APPLIED MATERIALS & INTERFACES, 2 (2), pp. 443-451.
  • Daar E, Kaabar W, Lei C, Keddie JL, Nisbet A, Bradley DA. (2010) 'AFM and uni-axial testing of pericardium exposed to radiotherapy doses'. Elsevier Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 652 (1), pp. 874-877.
  • Intaniwet A, Mills CA, Shkunov M, Thiem H, Keddie JL, Sellin PJ. (2009) 'Characterization of thick film poly(triarylamine) semiconductor diodes for direct x-ray detection'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 106 (6) Article number ARTN 064513
  • Bradley M, Liu D, Keddie JL, Vincent B, Burnett G. (2009) 'The Uptake and Release of Cationic Surfactant from polyampholyte Microgel Particles in Dispersion and as an Adsorbed Monolayer'. AMER CHEMICAL SOC LANGMUIR, 25 (17), pp. 9677-9683.
  • Liu D, Wang T, Keddie JL. (2009) 'Protein Nanopatterning on Self-Organized Poly(styrene-b-isoprene) Thin Film Templates'. American Chemical Society LANGMUIR, 25 (8), pp. 4526-4534.

    Abstract

    Templated surfaces can be used to create patterns of proteins for applications in cell biology, biosensors, and tissue engineering. A diblock copolymer template, which contains a pair of hydrophobic blocks, has been developed. The template is created from well-ordered, nonequilibrium surface structures of poly(styrene-b-isoprene) (PS-b-PI) diblock copolymers, which are achieved in ultrathin films having a thickness of less than one domain period. Adsorption and nanopatterning of bovine serum albumin (BSA) on these thin films were studied. After incubation of the copolymer templates in BSA solutions (500 μg/mL) for a period of 1 h, BSA molecules formed either a striped or a dense, ringlike structure, closely resembling the underlying polymer templates. In this “hard-soft” PS-b-PI system, BSA molecules were preferentially adsorbed on the hard PS domains, rather than on the soft PI domains. Secondary ion mass spectroscopy (SIMS) and contact angle analysis revealed that, with more PI localized at the free surface, fewer BSA molecules were adsorbed. SIMS analysis confirmed that BSA molecules were adsorbed selectively on the PS blocks. This is the first example of two hydrophobic blocks of a diblock copolymer being used as a protein patterning template. Previously reported diblock copolymer templates used hydrophilic and hydrophobic pairs. A potentially useful characteristic of this template is that it is effective at high protein solution concentrations (up to 1 mg/mL) and for long incubation times (up to 2 h), which broadens its range of applicability in various uses.

  • Wang T, Canetta E, Weerakkody TG, Keddie JL, Rivas U. (2009) 'pH dependence of the properties of waterborne pressure-sensitive adhesives containing acrylic acid.'. ACS Appl Mater Interfaces, United States: 1 (3), pp. 631-639.

    Abstract

    Polymer colloids are often copolymerized with acrylic acid monomers in order to impart colloidal stability. Here, the effects of the pH on the nanoscale and macroscopic adhesive properties of waterborne poly(butyl acrylate-co-acrylic acid) films are reported. In films cast from acidic colloidal dispersions, hydrogen bonding between carboxylic acid groups dominates the particle-particle interactions, whereas ionic dipolar interactions are dominant in films cast from basic dispersions. Force spectroscopy using an atomic force microscope and macroscale mechanical measurements show that latex films with hydrogen-bonding interactions have lower elastic moduli and are more deformable. They yield higher adhesion energies. On the other hand, in basic latex, ionic dipolar interactions increase the moduli of the dried films. These materials are stiffer and less deformable and, consequently, exhibit lower adhesion energies. The rate of water loss from acidic latex is slower, perhaps because of hydrogen bonding with the water. Therefore, although acid latex offers greater adhesion, there is a limitation in the film formation.

  • Wang T, Keddie JL. (2009) 'Design and fabrication of colloidal polymer nanocomposites'. ELSEVIER SCIENCE BV Advances in Colloid and Interface Science, 147-148, pp. 319-332.

    Abstract

    It is well established that colloidal polymer particles can be used to create organised structures by methods of horizontal deposition, vertical deposition, spin-casting, and surface pattern-assisted deposition. Each particle acts as a building block in the structure. This paper reviews how two-phase (or hybrid) polymer colloids can offer an attractive method to create nanocomposites. Structure in the composite can be controlled at the nanoscale by using such particles. Methods to create armored particles, such as via methods of hetero-flocculation and Pickering polymerization, are of particular interest here. Polymer colloids can also be blended with other types of nanoparticles, e.g. nanotubes and clay platelets, to create nanocomposites. Structure can be controlled over length scales approaching the macroscopic through the assembly of hybrid particles or particle blends via any of the various deposition methods. Colloidal nanocomposites can offer unprecedented long-range 2D or 3D order that provides a periodic modulation of physical properties. They can also be employed as porous templates for further nanomaterial fabrication. Challenges in the design and control of the macroscopic properties, especially mechanical, are considered. The importance of the internal interfacial structure (e.g. between inorganic and polymer particles) is highlighted.

  • Canetta E, Marchal J, Lei C-H, Deplace F, Koenig AM, Creton C, Ouzineb K, Keddie JL. (2009) 'A Comparison of Tackified, Miniemulsion Core-Shell Acrylic Latex Films with Corresponding Particle-Blend Films: Structure-Property Relationships'. AMER CHEMICAL SOC LANGMUIR, 25 (18), pp. 11021-11031.
  • Nikonenko NA, Bushnak IA, Keddie JL. (2009) 'Spectroscopic ellipsometry of mucin layers on an amphiphilic diblock copolymer surface'. Applied Spectroscopy, 63 (8), pp. 889-898.
  • Deplace F, Rabjohns MA, Yamaguchi T, Foster AB, Carelli C, Lei C-H, Ouzineb K, Keddie JL, Lovell PA, Creton C. (2009) 'Deformation and adhesion of a periodic soft-soft nanocomposite designed with structured polymer colloid particles'. ROYAL SOC CHEMISTRY SOFT MATTER, 5 (7), pp. 1440-1447.
  • Wang T, Colver PJ, Bon SAF, Keddie JL. (2009) 'Soft polymer and nano-clay supracolloidal particles in adhesives: synergistic effects on mechanical properties'. ROYAL SOC CHEMISTRY SOFT MATTER, 5 (20), pp. 3842-3849.
  • Keddie JL. (2009) 'Mapping the route from wet to dry'. European Coatings Journal, (11), pp. 28-32.
  • Rodriguez R, Alarcon CDLH, Ekanayake P, McDonald PJ, Keddie JL, Barandiaran MJ, Asua JM. (2008) 'Correlation of Silicone Incorporation into Hybrid Acrylic Coatings with the Resulting Hydrophobic and Thermal Properties'. AMER CHEMICAL SOC MACROMOLECULES, 41 (22), pp. 8537-8546.
  • Wang T, Dalton AB, Keddie JL. (2008) 'Importance of Molecular Friction in a Soft Polymer-Nanotube Nanocomposite'. AMER CHEMICAL SOC MACROMOLECULES, 41 (20), pp. 7656-7661.
  • Kessel N, Illsley DR, Keddie JL. (2008) 'The diacetone acrylamide crosslinking reaction and its influence on the film formation of an acrylic latex'. SPRINGER JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Toronto, CANADA: 5 (3), pp. 285-297.
  • Koenig AM, Weerakkody TG, Keddie JL, Johannsmann D. (2008) 'Heterogeneous drying of colloidal polymer films: Dependence on added salt'. American Chemical Society LANGMUIR, 24 (14), pp. 7580-7589.

    Abstract

    Using magnetic resonance profiling coupled with dynamic light scattering, we have investigated the mechanisms leading to the formation of a partly coalesced surface layer, or “open skin”, during film formation from waterborne polymer dispersions. We present the first use of the skewness of the distribution of free water as a model-free indicator of the spatial nonuniformity of drying. The skewness reaches a maximum at the same time at which a strong, static component, presumably originating from a skin at the film/air interface, appears in the light scattering data. Addition of salt to the dispersion increases both the skewness of the distribution of free water and the propensity for skin formation. Surprisingly, the drying is influenced not only by the concentration and valency of the ions in the salt but also by the particular ion. At intermediate particle densities, added salt strongly lowers the cooperative diffusion coefficient, Dcoop. When the particles reach close packing, Dcoop sharply increases. If the particles readily coalesce, the effects of the increased diffusivity will be counteracted, thereby inducing the formation of a skin. A modified Peclet number, Pe, using Dcoop, is proposed, so that the presence of salt is explicitly considered. This modified Pe is able to predict the nonuniformity in drying that leads to skin formation.

  • Wang T, Lei C-H, Liu D, Manea M, Asua JM, Creton C, Dalton AB, Keddie JL. (2008) 'A molecular mechanism for toughening and strengthening waterborne nanocomposites'. WILEY-V C H VERLAG GMBH ADVANCED MATERIALS, 20 (1), pp. 90-+.
  • Selvakumaran J, Keddie JL, Ewins DJ, Hughes MP. (2008) 'Protein adsorption on materials for recording sites on implantable microelectrodes'. SPRINGER JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE, 19 (1), pp. 143-151.
  • Gundabala VR, Lei C-H, Ouzineb K, Dupont O, Keddie JL, Routh AF. (2008) 'Lateral Surface Nonuniformities in Drying Latex Films'. JOHN WILEY & SONS INC AICHE JOURNAL, 54 (12), pp. 3092-3105.
  • Wang T, Liu D, Keddie JL. (2007) 'An alternative approach to the modification of talc for the fabrication of polypropylene/Talc composites'. JOHN WILEY & SONS INC JOURNAL OF APPLIED POLYMER SCIENCE, 106 (1), pp. 386-393.
  • Nerapusri V, Keddie JL, Vincent B, Bushnak LA. (2007) 'Absorption of cetylpyridinium chloride into Poly(N-isopropylacrylamide)-Based microgel particles, in dispersion and as surface-deposited monolayers'. 5th Edition. AMER CHEMICAL SOC LANGMUIR, 23 (19), pp. 9572-9577.

    Abstract

    The addition of cetylpyridinium chloride (CPC) to aqueous dispersions of poly(N-isopropylacrylamide) [poly(NIPAM)] and poly(N-isopropylacrylamide-co-acrylic acid) [poly(NIPAM-co-AAc)] microgel particles leads to absorption of the CPC into the particles and to corresponding changes in their hydrodynamic diameter. With the latter set of particles there is a strong pH dependence. The dependence of both hydrodynamic diameter and electrophoretic mobility of the microgel particles on the added CPC concentration show a strong correlation with CPC uptake, as obtained from direct CPC absorption measurements. Various mechanisms for CPC absorption into the microgel particles are postulated, including electrostatic, polar, and hydrophobic interactions. A comparison has also been made between the effect of added CPC on the hydrodynamic diameter of free microgel particles in dispersion, determined by dynamic light scattering, and the thickness of adsorbed monolayers of the same microgel particles deposited on cationically modified, oxidized silicon surfaces, as determined from ellipsometry measurements. The trends observed in both cases are broadly similar. This work opens the way for development of microgel layers for controlled uptake and release applications.

  • Keddie JL, Wang T, Jurewicz I, Dalton AB, Creton C, Manea M, Asua JM. (2007) 'Multifunctional nanocomposites of soft polymer colloids and carbon nanotubes'. AMER CHEMICAL SOC ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 234
  • Keddie JL, Ekanayake P, Koenig AM, Weerakkody TG, Barber N, Johannsmann D, Sear RP, McDonald PJ. (2007) 'Influence of the colloidal stability of latex particles on their distribution in drying films'. AMER CHEMICAL SOC ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 234
  • Boroumand FA, Zhu M, Dalton AB, Keddie JL, Sellin PJ, Gutierrez JJ. (2007) 'Direct x-ray detection with conjugated polymer devices'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 91 (3) Article number ARTN 033509
  • Lei C-H, Ouzineb K, Dupont O, Routh AF, Gundabala VR, Hinder SJ, Keddie JL. (2007) 'Lateral distribution of surfactants in waterborne pressure sensitive adhesive films: Theory and experiment'. AMER CHEMICAL SOC ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 233
  • Wang T, Lei C-H, Dalton AB, Manea M, Asua JM, Keddie JL. (2007) 'Waterborne nanocomposite pressure-sensitive adhesives: Achieving enhanced adhesion combined with electrical conductivity'. AMER CHEMICAL SOC ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 233
  • Wang T, Lei C-H, Dalton AB, Manea M, Asua JM, Keddie JL. (2007) 'COLL 306-Waterborne nanocomposite pressure-sensitive adhesives: Achieving enhanced adhesion combined with electrical conductivity'. AMER CHEMICAL SOC ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 233
  • Lei CH, Keddie JL, Ouzineb K, Dupont O. (2007) 'Probing particle structure in waterborne pressure-sensitive adhesives with atomic force microscopy'. Journal of Colloid and Interface Science, 307 (1), pp. 56-63.

    Abstract

    There is a need to know the nanostructure of pressure-sensitive adhesive (PSA) films obtained from waterborne polymer colloids so that it can be correlated with properties. Intermittent-contact atomic force microscopy (AFM) of an acrylic waterborne PSA film identifies two components, which can be attributed to the polymer and the solids in the serum (mainly surfactant). It is found that when the average AFM tapping force, F, is relatively low, the polymer particles appear to be concave. But when F is higher, the particles appear to have a convex shape. This observation is explained by a height artefact caused by differences in the indentation depths into the two components that vary with the tapping amplitude and F. To achieve the maximum contrast between the polymer and serum components, F should be set such that the indentation depths are as different as possible. Unlike what is found for the height images, the phase contrast images of the PSA do not show a reversal in contrast over the range of tapping conditions applied. The phase images are thus reliable in distinguishing the two components of the PSA according to their viscoelastic properties. At the surface of films dried at room temperature, the serum component is found in localized regions within permanent depression into the film. © 2006 Elsevier Inc. All rights reserved.

  • Adikaari AADT, Carey JD, Stolojan V, Keddie JL, Silva SRP. (2006) 'Bandgap enhancement of layered nanocrystalline silicon from excimer laser crystallization'. IOP PUBLISHING LTD NANOTECHNOLOGY, 17 (21), pp. 5412-5416.
  • Nerapusri V, Keddie JL, Vincent B, Bushnak IA. (2006) 'Swelling and deswelling of adsorbed microgel monolayers triggered by changes in temperature, pH, and electrolyte concentration'. AMER CHEMICAL SOC LANGMUIR, 22 (11), pp. 5036-5041.
  • Mallegol J, Bennett G, McDonald PJ, Keddie JL, Dupont O. (2006) 'Skin development during the film formation of waterborne acrylic pressure-sensitive adhesives containing tackifying resin'. TAYLOR & FRANCIS LTD J ADHESION, 82 (3), pp. 217-238.
  • Wang T, Lei C-H, Dalton AB, Keddie JL, Creton C, Lin Y, Fernando KAS, Sun Y-P, Manea M, Asua JM. (2006) 'Waterborne, nanocomposite pressure-sensitive adhesives with high tack energy, optical transparency, and electrical conductivity'. Advanced Materials, 18 (20), pp. 2730-2734.
  • Vandervorst P, Lei C-H, Lin Y, Dupont O, Dalton AB, Sun Y-P, Keddie JL. (2006) 'The fine dispersion of functionalized carbon nanotubes in acrylic latex coatings'. Elsevier Progress in Organic Coatings, 57 (2), pp. 91-97.

    Abstract

    Nanocomposites of a polymer and carbon nanotubes exhibit high electrical and thermal conductivity and enhanced mechanical properties in comparison to the polymer alone. Film formation from latex dispersions is an ideal way to create nanocomposite coatings with the advantages of solvent-free processing and a high uniformity of dispersion. It is shown here that carbon nanotubes functionalised with poly(vinyl alcohol) (PVA) can be blended with two types of acrylic latex to create stable colloidal dispersions without the need for added surfactant or emulsifier. Waterborne nanocomposite films with optical transparency can be formed. Microscopic analysis shows that the PVA-functionalized nanotubes are finely and uniformly dispersed in the polymer matrix.

  • Duckworth P, Richardson H, Carelli C, Keddie JL. (2005) 'Infrared ellipsometry of interdiffusion in thin films of miscible polymers'. Surface and Interface Analysis, 37 (1), pp. 33-41.
  • Keddie JL, Lopez-Garcia I, Richardson H, Sferrazza M. (2004) 'Thickness dependence of structural relaxation in spin-cast, glassy polymer thin films'. American Physical Society Physical Review E, 70 Article number 051805

    Abstract

    The isothermal structural relaxation of glassy, spin-cast polymer thin films has been investigated. Specifically, the thickness, h, of freshly-cast poly(methyl methacrylate) thin films was measured over time using spectroscopic ellipsometry. The spin-cast films exhibit a gradual decrease in thickness, which is attributed to structural relaxation of the glass combined with simultaneous solvent loss. In all cases, h was found to be greater than the equilibrium thickness, h0, which is obtained by cooling slowly from the melt. It is observed that both the rate of the volume relaxation and the fractional departure from h0 (referred to as ∂o) increase with increasing film thickness. In the limit of very thin films, the initial h is close to h, and o is small, whereas in thick films (> 500 nm), a plateau value of ∂o of 0.16 is observed, which is close to the volume fraction of the solvent at the vitrification point. This dependence of ∂o on thickness is observed regardless of the substrate, polymer molecular weight, or angular velocity during spin-casting. Enhanced mobility near film surfaces could be leading to greater relaxation in thinner films prior to, and immediately after, the vitrification of the polymer during the deposition process.

  • Simpson TRE, Tabatabaian Z, Jeynes C, Parbhoo B, Keddie JL. (2004) 'Influence of interfaces on the rates of crosslinking in poly(dimethyl siloxane) coatings'. JOHN WILEY & SONS INC JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, 42 (6), pp. 1421-1431.
  • Keddie JL, McDonald PJ, Gorce J-P, Mallégol J. (2004) 'Understanding water-borne coatings: New techniques to answer old questions'. Surface Coatings International Part A: Coatings Journal, 87 (2), pp. 70-73.
  • Lincoln BJ, Simpson TRE, Keddie JL. (2004) 'Water vapour sorption by the pedal mucus trail of a land snail'. Elsevier Colloids and Surfaces B: Biointerfaces, 33 (3-4), pp. 251-258.
  • Richardson H, Sferrazza M, Keddie JL. (2003) 'Influence of the glass transition on solvent loss from spin-cast glassy polymer thin films.'. Eur Phys J E Soft Matter, France: 12 Suppl 1, pp. S87-S91.
  • Richardson H, Carelli C, Keddie JL, Sferrazza M. (2003) 'Structural relaxation of spin-cast glassy polymer thin films as a possible factor in dewetting.'. Springer Eur Phys J E Soft Matter, France: 12 (3), pp. 437-440.

    Abstract

    Reiter has recently reported a situation in which the dewetting of quasi-solid films is linked to plastic deformation--rather than viscous flow--resulting from capillary forces. Herein we propose that, in thin films of some glassy polymers--especially poly(methyl methacrylate) (PMMA)--prepared by spin-casting from solvent, structural relaxation might impart sufficient stress to cause plastic deformation. We find that PMMA films decrease in thickness by several percent, which is sufficient to create significant stress in those cases in which the film is attached to a rigid substrate. The floating technique, which can take tens of minutes, might allow most of the structural relaxation to occur prior to dewetting experiments.

  • Aramendia E, Mallegol J, Jeynes C, Barandiaran MJ, Keddie JL, Asua JM. (2003) 'Distribution of surfactants near acrylic latex film surfaces: A comparison of conventional and reactive surfactants (surfmers)'. AMER CHEMICAL SOC LANGMUIR, 19 (8), pp. 3212-3221.
  • Bennett G, Gorce JP, Keddie JL, McDonald PJ, Berglind H. (2003) 'Magnetic resonance profiling studies of the drying of film-forming aqueous dispersions and glue layers.'. Magn Reson Imaging, United States: 21 (3-4), pp. 235-241.
  • Simpson TRE, Keddie JL, Parbhoo B. (2003) 'The dependence of the rate of crosslinking in poly(dimethyl siloxane) on the thickness of coatings'. Polymer, 44 (17), pp. 4829-4838.
  • Richardson H, Sferrazza M, Keddie JL. (2003) 'Influence of the glass transition on solvent loss from spin-cast glassy polymer thin films'. European Physical Journal E, 12 (SUPPL. 1), pp. 75-79.
  • Richardson H, Sferrazza M, Keddie JL. (2003) 'Slow relaxation of spin-cast poly(methyl methacrylate) confined in thin films'. Materials Research Society Materials Research Society Symposium - Proceedings, 790, pp. 251-256.
  • Mallegol J, Dupont O, Keddie JL. (2003) 'Morphology and elasticity of waterborne acrylic pressure-sensitive adhesives investigated, with atomic force microscopy'. JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY, 17 (2), pp. 243-259.

    Abstract

    The morphology of pressure sensitive adhesives (PSAs), especially at the surface in contact with a release liner, is expected to have a dominant influence on the tack strength and energy in an application. We have used tapping-mode atomic force microscopy to determine the morphology at the surfaces of freshly-cast waterborne acrylic PSAs over lateral length scales of a few m. We demonstrate that topographical features on silicone release liners can be used to pattern the PSA surface in contact with it. Control of the texture of a PSA surface can potentially be exploited to tailor its properties. Latex particle boundaries are much better defined at the air surface of the PSA in comparison to its back face. A series of experiments suggests that this difference results from the distribution of water-soluble species within the dry film. The pressures and processes involved in the transfer lamination process do not alter the PSA morphology. The first reported AFM images of the response of these materials to pressure and shear provide insight into the deformation mechanisms. Amplitude-distance curves on PSA surfaces show that there is a small decrease in tack and an increase in stiffness after ageing for 13 months.

  • Simpson TRE, Keddie JL. (2003) 'Evidence from infrared ellipsometry for covalent bonding at a polymer/polymer interface with relevance to "lock-up" in pressure-sensitive adhesive laminates'. Taylor and Francis Journal of Adhesion, 79 (12), pp. 1207-1218.
  • Mallegol J, Barry AM, Ciampi E, Glover PM, McDonald PJ, Keddie JL, Wallin M, Motiejauskaite A, Weissenborn PK. (2002) 'Influence of drier combination on through-drying in waterborne alkyd emulsion coatings observed with magnetic resonance profiling'. FEDERATION SOC COATING TECH JOURNAL OF COATINGS TECHNOLOGY, 74 (933), pp. 113-124.
  • Gorce JP, Bovey D, McDonald PJ, Palasz P, Taylor D, Keddie JL. (2002) 'Vertical water distribution during the drying of polymer films cast from aqueous emulsions.'. Eur Phys J E Soft Matter, France: 8 (4), pp. 421-429.
  • Mallegol J, Gorce JP, Dupont O, Jeynes C, McDonald PJ, Keddie JL. (2002) 'Origins and effects of a surfactant excess near the surface of waterborne acrylic pressure-sensitive adhesives'. AMER CHEMICAL SOC LANGMUIR, 18 (11), pp. 4478-4487.
  • Zhao Y, Carey JD, Knoops N, Maetens D, Hopkinson I, Hay JN, Keddie JL. (2002) 'Inhibition of the surface levelling of thermosetting polyester powder coatings caused by surface tension gradients'. Springer Journal of Materials Science, 37 (22), pp. 4759-4768.

    Abstract

    Previous theoretical and experimental work has shown that surface tension gradients in liquid layers create surface defects and inhibit the levelling of an uneven surface. In coatings deposited from thermosetting polyester powders, which are studied here, small amounts of a low molecular-weight acrylate are incorporated to act as a “flow agent.” We find that this additive lowers the surface tension of the polymer melt and has a minor effect on the melt viscosity. A slower rate of levelling results from the decreased surface tension. We provide experimental evidence that lateral gradients in the surface tension of the polymer melt, resulting from the non-uniform distribution of the flow agent, inhibit the levelling of the surface. Specifically, the surface roughness of a powder coating is up to three times greater when a steep surface tension gradient is purposely created through powder blending. Surface tension gradients might also be responsible for the greater surface roughness (observed with atomic force microscopy on lateral length scales of 100 μm) that is found in coatings that contain flow agent.

  • Keddie JL, Gorce JP, Mallegol J, Wallin M, Barry AM, Ciampi E, Motiejauskaite A, Glover PM, McDonald PJ, Weissenborn PK. (2001) 'MR profiling of film formation and crosslinking in waterborne alkyd emulsions and emulsion paints.'. AMER CHEMICAL SOC ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 222, pp. U378-U378.
  • Mallegol J, Keddie JL, Dupont O. (2001) 'New insights into the imaging of waterborne acrylic pressure-sensitive adhesives by tapping mode AFM.'. ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 222, pp. U346-U346.
  • Salamanca JM, Ciampi E, Faux DA, Glover PM, McDonald PJ, Routh AF, Peters ACIA, Satguru R, Keddie JL. (2001) 'Lateral drying in thick films of waterborne colloidal particles'. AMER CHEMICAL SOC LANGMUIR, 17 (11), pp. 3202-3207.
  • Sackin R, Ciampi E, Godward J, Keddie JL, McDonald PJ. (2001) 'Fickian ingress of binary solvent mixtures into glassy polymer'. AMER CHEMICAL SOC MACROMOLECULES, 34 (4), pp. 890-895.
  • Keddie J, Mallégol J, Dupont O. (2001) 'The technological and environmental pressures on advanced adhesives'. Materials World, 9 (11), pp. 22-24.
  • Mallégol J, Keddie JL, Dupont O. (2001) 'Etude structurale des films d'adhesifs acryliques sensibles a la pression par microscopie a force atomique en mode tapping'. Vide: Science, Technique et Applications, (302 SUPPL.), pp. 34-37.
  • Holl Y, Keddie JL, McDonald PJ, Winnik WA. (2001) 'Drying modes of polymer colloids'. ACS Symposium Series, 790, pp. 2-26.
  • Andrei DC, Keddie JL, Hay JN, Yeates SG, Briscoe BJ, Parsonage D. (2001) 'Nano-mechanical properties and topography of thermosetting acrylic powder coatings'. JOURNAL OF COATINGS TECHNOLOGY, 73 (912), pp. 65-73.
  • Mallégol J, Dupont O, Keddie JL. (2001) 'Obtaining and interpreting images of waterborne acrylic pressure-sensitive adhesives by tapping-mode atomic force microscopy'. Langmuir, 17 (22), pp. 7022-7031.
  • Tzitzinou A, Keddie JL, Geurts JL, Mulder M, Satguru R, Treacher KE. (2001) 'Molecular weight effects on the film formation of latex and on surfactant distribution and morphology'. ACS Symposium Series, 790, pp. 58-87.
  • Keddie JL. (2001) 'Structural analysis of organic interfacial layers by ellipsometry'. Current Opinion in Colloid and Interface Science, 6 (2), pp. 102-110.
  • Malucelli G, Sangermano M, Bongiovanni R, Priola A, Keddie JL. (2000) 'Water sorption in polymer network films synthesised from PEO oligomers containing acrylic and vinyl ether functionalities'. POLYMER BULLETIN, 45 (4-5), pp. 431-438.
  • Wallin M, Glover PM, Hellgren AC, Keddie JL, McDonald PJ. (2000) 'Depth profiles of polymer mobility during the film formation of a latex dispersion undergoing photoinitiated cross-linking'. AMER CHEMICAL SOC MACROMOLECULES, 33 (22), pp. 8443-8452.
  • Ciampi E, Goerke U, Keddie JL, McDonald PJ. (2000) 'Lateral transport of water during drying of alkyd emulsions'. AMER CHEMICAL SOC LANGMUIR, 16 (3), pp. 1057-1065.
  • McMurtry S, Wright JD, Jackson DA, Keddie JL. (2000) 'Humidity sensing using PMMA-PMTGA-PMMA polymer in low coherence interferometric system'. ELECTRONICS LETTERS, 36 (1), pp. 73-74.
  • Gilchrist VA, Lu JR, Keddie JL, Staples E, Garrett P. (2000) 'Adsorption of penta(ethylene glycol) monododecyl ether at the solid poly(methyl methacrylate)-water interface: A spectroscopic ellipsometry study'. Langmuir, 16 (2), pp. 740-748.
  • Andrei DC, Hay JN, Keddie JL, Sear RP, Yeates SG. (2000) 'Surface levelling of thermosetting powder coatings: theory and experiment'. Journal of Physics D: Applied Physics, 33 (16), pp. 1975-1981.
  • Tzitzinou A, Keddie JL, Geurts JM, Peters ACIA, Satguru R. (2000) 'Film formation of latex blends with bimodal particle size distributions: Consideration of particle deformability and continuity of the dispersed phase'. Macromolecules, 33 (7), pp. 2695-2708.
  • Parbhoo B, Izraej S, Salamanca JM, Keddie JL. (2000) 'Use of ellipsometry and gravimetry to develop calibration standards for measuring silicone coat weight and thickness with x-ray fluorescence spectroscopy'. Surface and Interface Analysis, 29 (5), pp. 341-345.
  • Styrkas DA, Lu JR, Keddie JL, Bütün V, Armes SP. (2000) 'pH-controlled adsorption of polyelectrolyte diblock copolymers at the solid/liquid interface'. Langmuir, 16 (14), pp. 5980-5986.
  • Tzitzinou A, Keddie JL, Jeynes C, Mulder M, Geurts J, Treacher KE, Satguru R, Zhdan P. (1999) 'Molecular weight effects on film formation of latex and surfactant morphology.'. AMER CHEMICAL SOC ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 218, pp. U609-U609.
  • Keddie JL, Andrei DC, Sear RPL, Yeates SG. (1999) 'Surface flattening of thermosetting powder coatings: Theory and experiment.'. AMER CHEMICAL SOC ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 218, pp. U626-U626.
  • Keddie JL, Ciampi E, McDonald PJ, Salamanca JM. (1999) 'Magnetic resonance imaging of the film formation of waterborne coatings.'. ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 218, pp. U621-U621.
  • Murphy EF, Keddie JL, Lu JR, Brewer J, Russell J. (1999) 'The reduced adsorption of lysozyme at the phosphorylcholine incorporated polymer/aqueous solution interface studied by spectroscopic ellipsometry.'. Biomaterials, ENGLAND: 20 (16), pp. 1501-1511.
  • McDonald PJ, Ciampi E, Keddie JL, Heidenreich M, Kimmich R. (1999) 'Magnetic-resonance determination of the spatial dependence of the droplet size distribution in the cream layer of oil-in-water emulsions: Evidence for the effects of depletion flocculation'. The American Physical Society Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, 59 (1), pp. 874-884.

    Abstract

    It is shown that a combination of pulsed-field-gradient spin-echo ~PGSE! nuclear-magnetic-resonance~NMR! restricted diffusion analysis and NMR imaging may be used to measure the spatial dependence of the droplet size distribution in the cream layer of turbid oil-in-water emulsions. 1H-13C cyclic J cross-polarization PGSE is introduced as a technique for this purpose in cases where selective observation of the oil component ~or other carbohydrate constituent! is required. With this method, 13C nuclei are chemical shift selectively excited by cross-polarization from coupled 1H partners. An optimum detection sensitivity is ensured by transferring the polarization back to the coupled protons with which the combined imaging and diffusion experiment is then carried out. The spatial dependence of the oil droplet size distribution was measured for a series of emulsions containing various fractions of gum xanthan thickener dissolved in the water. The experimental results are compared with a recent model of the creaming process due to Pinfield, Dickinson, and Povey @J. Colloid Interface Sci. 166, 363 ~1994!#. When no gum xanthan is present, the experimental results are in good agreement with the model. However, the model fails to describe the droplet distribution for emulsions with a gum xanthan concentration of the order of 0.1 wt %. The discrepancy is discussed in terms of depletion flocculation and depletion stabilization.

  • Bero MA, Gilboy WB, Glover PM, Keddie JL. (1999) 'Three-dimensional radiation dose measurements with Ferrous Benzoic Acid Xylenol Orange in Gelatin gel and optical absorption tomography'. Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 422 (1-3), pp. 617-620.
  • Barradas NP, Keddie JL, Sackin R. (1999) 'Bayesian inference analysis of ellipsometry data'. Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, 59 (5), pp. 6138-6151.

    Abstract

    Variable angle spectroscopic ellipsometry is a nondestructive technique for accurately determining the thicknesses and refractive indices of thin films. Experimentally, the ellipsometry parameters ψ and Δ are measured, and the sample structure is then determined by one of a variety of approaches, depending on the number of unknown variables. The ellipsometry parameters have been inverted analytically for only a small number of sample types. More general cases require either a model-based numerical technique or a series of approximations combined with a sound knowledge of the test sample structure. In this paper, the combinatorial optimization technique of simulated annealing is used to perform least-squares fits of ellipsometry data (both simulated and experimental) from both a single layer and a bilayer on a semi-infinite substrate using what is effectively a model-free system, in which the thickness and refractive indices of each layer are unknown. The ambiguity inherent in the best-fit solutions is then assessed using Bayesian inference. This is the only way to consistently treat experimental uncertainties along with prior knowledge. The Markov chain Monte Carlo algorithm is used. Mean values of unknown parameters and standard deviations are determined for each and every solution. Rutherford backscattering spectrometry is used to assess the accuracy of the solutions determined by these techniques. With our computer analysis of ellipsometry data, we find all possible models that adequately describe that data. We show that a bilayer consisting of a thin film of poly(styrene) on a thin film of silicon dioxide on a silicon substrate results in data that are ambiguous; there is more than one acceptable description of the sample that will result in the same experimental data.

  • Chen W-L, Shull KR, Papatheodorou T, Styrkas DA, Keddie JL. (1999) 'Equilibrium swelling of hydrophilic polyacrylates in humid environments'. Macromolecules, 32 (1), pp. 136-144.
  • Styrkas DA, Keddie JL, Lu JR, Su TJ, Zhdan PA. (1999) 'Structure of self-assembled layers on silicon: Combined use of spectroscopic variable angle ellipsometry, neutron reflection, and atomic force microscopy'. Journal of Applied Physics, 85 (2), pp. 868-875.

    Abstract

    Neutron reflection (NR), spectroscopic ellipsometry (SE), and atomic force microscopy (AFM) have been used to characterize the structure of self-assembled octadecyltrichlorosilane (OTS) layers on silicon. The first two of these techniques rely on modeling of the experimental data and may thus result in the unrealistic representation of the composition and structure at the interface. Ambiguities arise from model-dependent analysis complicated by the lack of sufficient external constraints to converge nonunique solutions to a unique one. We show in this work that AFM measurements provide extra constraints to allow us to obtain a physical description closer to the actual structure of the film. It was found that “the simpler the better” modeling strategy very often employed during the fitting of ellipsometric and neutron reflection data is, therefore, not necessarily the best way to obtain a reliable description of the interfacial structure. Our AFM findings necessitated the refit of both neutron and ellipsometric data that were previously described by a single-layer model. Interpretation of the structure of thin layers that is based only on indirect measurements such as SE, NR, and x-ray reflection techniques may be, therefore, misleading. A combined analysis of SE, NR, and AFM data suggests that the OTS film may comprise a rough layer, with pinholes down to bare silicon oxide surface, consisting at least of mono-, bi- and trilayers of OTS molecules.

  • Tzitzinou A, Jenneson PM, Clough AS, Keddie JL, Lu JR, Zhdan P, Treacher KE, Satguru R. (1999) 'Surfactant concentration and morphology at the surfaces of acrylic latex films'. Progress in Organic Coatings, 35 (1-4), pp. 89-99.
  • Cappellani A, Keddie JL, Barradas NP, Jackson SM. (1999) 'Processing and characterization of sol-gel deposited TaO and TiO-TaO dielectric thin films'. Solid-State Electronics, 43 (6), pp. 1095-1099.
  • Newling B, Glover PM, Keddie JL, Lane DM, McDonald PJ. (1997) 'Concentration profiles in creaming oil-in-water emulsion layers determined with stray field magnetic resonance imaging'. Langmuir, 13 (14), pp. 3621-3626.
  • Clough AS, Jenneson PM, Keddie JL. (1997) 'Ion beam analysis of small molecule diffusion in polymers'. Annual Technical Conference - ANTEC, Conference Proceedings, 2, pp. 2211-2215.
  • Jenneson PM, Clough AS, Keddie JL, Lu JR, Meredith P. (1997) 'Non-ionic surfactant concentration profiles in undamaged and damaged hair fibres determined by scanning ion beam nuclear reaction analysis'. Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms, 132 (4), pp. 697-703.
  • Keddie JL. (1997) 'Film formation of latex'. Materials Science and Engineering R: Reports, 21 (3), pp. 101-170.
  • Keddie JL, Meredith P, Jones RAL, Donald AM. (1996) 'Rate-Limiting Steps in Film Formation of Acrylic Latices as Elucidated with Ellipsometry and Environmental Scanning Electron Microscopy'. ACS Symposium Series, 648, pp. 332-348.
  • Keddie JL, Meredith P, Jones RAL, Donald AM. (1996) 'Film formation of acrylic latices with varying concentrations of non-film-forming latex particles'. Langmuir, 12 (16), pp. 3793-3801.
  • KEDDIE J, MEREDITH P, JONES R, DONALD A. (1995) 'RATE-LIMITING STEPS IN THE FILM FORMATION OF WATER-BORNE ACRYLIC LATTICES AS ELUCIDATED WITH ELLIPSOMETRY AND ENVIRONMENTAL-SEM'. ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 210, pp. 76-PSME.
  • Keddie JL, Jones RAL. (1995) 'Depression of the glass transition temperature in ultra-thin, grafted polystyrene films'. Materials Research Society Symposium - Proceedings, 366, pp. 183-188.
  • Keddie JL, Meredith P, Jones RAL, Donald AM. (1995) 'Kinetics of film formation in acrylic latices studied with multiple-angle-of-incidence ellipsometry and environmental SEM'. Macromolecules, 28 (8), pp. 2673-2682.
  • KEDDIE J, JONES R. (1995) 'GLASS-TRANSITION BEHAVIOR IN ULTRA-THIN POLYSTYRENE FILMS'. ISRAEL JOURNAL OF CHEMISTRY, 35 (1), pp. 21-26.
  • KEDDIE J, JONES R, CORY R. (1994) 'SIZE-DEPENDENT DEPRESSION OF THE GLASS-TRANSITION TEMPERATURE IN POLYMER-FILMS'. EUROPHYSICS LETTERS, 27 (1), pp. 59-64.
  • KEDDIE J, BRAUN P, GIANNELIS E. (1994) 'INTERRELATIONSHIP BETWEEN DENSIFICATION, CRYSTALLIZATION, AND CHEMICAL EVOLUTION IN SOL-GEL TITANIA THIN-FILMS'. JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 77 (6), pp. 1592-1596.
  • KEDDIE J, JONES R, CORY R. (1994) 'INTERFACE AND SURFACE EFFECTS ON THE GLASS-TRANSITION TEMPERATURE IN THIN POLYMER-FILMS'. FARADAY DISCUSSIONS, 98, pp. 219-230.
  • KEDDIE J, NORTON L, KRAMER E, GIANNELIS E. (1993) 'NEUTRON REFLECTOMETRY CHARACTERIZATION OF INTERFACE WIDTH BETWEEN SOL-GEL TITANIUM-DIOXIDE AND SILICON DIOXIDE THIN-FILMS'. JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 76 (10), pp. 2534-2538.
  • KEDDIE J, BRAUN P, GIANNELIS E. (1993) 'RELATIONSHIP BETWEEN WATER DESORPTION AND LOW-TEMPERATURE DENSIFICATION OF COLLOIDAL ANATASE THIN-FILMS'. JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 76 (10), pp. 2529-2533.
  • LEVINE T, KEDDIE J, REVESZ P, MAYER J, GIANNELIS E. (1993) 'ION-BEAM-INDUCED DENSIFICATION OF ZIRCONIA SOL-GEL THIN-FILMS'. JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 76 (5), pp. 1369-1379.
  • KEDDIE J, LI J, MAYER J, GIANNELIS E. (1991) 'EFFECT OF NITRIDATION RATE ON THE COMPOSITION AND CONDUCTIVITY OF TITANIUM NITRIDE FILMS PREPARED FROM SOL-GEL TITANIA'. JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 74 (11), pp. 2937-2940.
  • KEDDIE J, GIANNELIS E. (1991) 'EFFECT OF HEATING RATE ON THE SINTERING OF TITANIUM-DIOXIDE THIN-FILMS - COMPETITION BETWEEN DENSIFICATION AND CRYSTALLIZATION'. JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 74 (10), pp. 2669-2671.
  • Mehrotra V, Keddie JL, Miller JM, Giannelis EP. (1991) 'Electrically conducting glasses: incorporation of polypyrrole in a porous SiO matrix'. Journal of Non-Crystalline Solids, 136 (1-2), pp. 97-102.
  • Keddie JL, Giannelis EP. (1990) 'Ion-beam analysis of silica sol-gel films. Structural and compositional evolution'. Journal of the American Ceramic Society, 73 (10), pp. 3106-3109.

Conference papers

  • Keddie JL, Utgenannt A, Kanaras AG, Muskens OL. (2013) 'Directed organization of gold nanoparticles in polymer coatings over large length scales through infrared-assisted evaporative lithography'. AMER CHEMICAL SOC ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, New Orleans, LA: 245th National Meeting of the American-Chemical-Society (ACS) 245
  • Keddie JL, Georgiadis A, Sansom H, Muhamad F. (2013) 'Bespoke patterned coatings via infrared radiation-assisted evaporative lithography: Moving colloids with modulated light'. AMER CHEMICAL SOC ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, New Orleans, LA: 245th National Meeting of the American-Chemical-Society (ACS) 245
  • Keddie JL, Gurney R, Dupin D, Siband E. (2013) 'Large-area patterning of the tackiness of a colloidal nanocomposite adhesive by sintering of nanoparticles under IR radiation'. AMER CHEMICAL SOC ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, New Orleans, LA: 245th National Meeting of the American-Chemical-Society (ACS) 245
  • Daar E, Woods E, Keddie JL, Nisbet A, Bradley DA. (2010) 'Effect of penetrating ionising radiation on the mechanical properties of pericardium'. ELSEVIER SCIENCE BV NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, Melbourne, AUSTRALIA: 11th International Symposium on Radiation Physics 619 (1-3), pp. 356-360.
  • Deplace F, Marchal J, Carelli C, Chateauminois A, Creton C, Rabjohns M, Foster A, Lovell PA, Lei C, Keddie J. (2009) 'Soft-soft nanocomposites for adhesive applications'. 12th International Conference on Fracture 2009, ICF-12, Ottawa, Canada: 2, pp. 1205-1211.
  • Ekanayake P, McDonald PJ, Keddie JL. (2009) 'An experimental test of the scaling prediction for the spatial distribution of water during the drying of colloidal films'. EDP SCIENCES S A/SPRINGER EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS, Paris, FRANCE: 7th Biannual European Coating Symposium 166 (1), pp. 21-27.
  • Mills CA, Intaniwet A, Shkunov M, Keddie JL, Sellin PJ. (2009) 'Flexible radiation dosimeters incorporating semiconducting polymer thick films'. SPIE Proceedings of SPIE - The International Society for Optical Engineering, San Diego, USA: Hard X-ray, gamma-ray, and neutron detector physics XI 7449

    Abstract

    Flexible radiation dosimeters have been produced incorporating thick films (>1 μm) of the semiconducting polymer poly([9,9-dioctylfluorenyl-2,7-diyl]-co-bithiophene). Diode structures produced on aluminium-metallised poly(imide) substrates, and with gold top contacts, have been examined with respect to their electrical properties. The results suggest that a Schottky conduction mechanism occurs in the reverse biased diode, with a barrier to charge injection at the aluminium electrode. Optical absorption/emission spectra reveal a band gap of 2.48 eV for the polymer. The diodes have been used for direct charge detection of 17 keV X-rays, generated by a molybdenum source. Using operating voltages of -10 and -50 V respectively, sensitivities of 54 and 158 nC/mGy/cm3 have been achieved. Increasing the operating voltage shows that the diodes are stable up to approximately -200 V without significant increase in the dark current of the device (<0.2 nA).

  • Simpson TRE, Keddie JL, Parbhoo B. (2003) 'IR ellipsometry of crosslinking in silicone coatings: Effect of thickness'. ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 225, pp. U702-U702.
  • Simpson TRE, Keddie JL, Parbhoo B. (2003) 'Influence of interfaces on the rate of crosslinking in silicone coatings.'. ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 225, pp. U710-U710.
  • Selvakumaran J, Hughes MP, Keddie JL, Ewins DJ. (2002) 'Assessing biocompatibility of materials for implantable microelectrodes using cytotoxicity and protein adsorption studies'. 2ND ANNUAL INTERNATIONAL IEEE-EMBS SPECIAL TOPIC CONFERENCE ON MICROTECHNOLOGIES IN MEDICINE & BIOLOGY, PROCEEDINGS, , pp. 261-264.
  • Hellgren AC, Wallin M, Weissenborn PK, McDonald PJ, Glover PM, Keddie JL. (2001) 'New techniques for determining the extent of crosslinking in coatings'. ELSEVIER SCIENCE SA PROGRESS IN ORGANIC COATINGS, ATHENS, GREECE: Conference on Organic Coatings and Technology 43 (1-3), pp. 85-98.
  • Styrkas D, Doran SJ, Gilchrist T, Keddie JL, Lu JR, Murphy E, Sackin R, Su TJ, Tzitzinou A. (1999) 'Application of ellipsometry to polymers at interfaces and in thin films'. POLYMER SURFACES AND INTERFACES III, , pp. 1-42.
  • Keddie JL, Cory RA, Jones RAL. (1998) 'Polymer dynamics in thin films'. MODERN ASPECTS OF COLLOIDAL DISPERSIONS, , pp. 149-157.
  • Keddie JL, Meredith P, Jones RAL, Donald AM. (1998) 'Film formation of latices'. MODERN ASPECTS OF COLLOIDAL DISPERSIONS, , pp. 51-59.

Books

  • Routh AF, Keddie J. (2010) Fundamentals of Latex Film Formation: Processes and Properties. Springer Verlag

Teaching

Year 1: Properties of Matter (PHY1039) - lectures and laboratory

Year 3: Soft Matter and Biological Physics (PHY3040)

MSc in Advanced Materials:  Lectures on Polymers and Nanomaterials

Departmental Duties

Senior Tutor for Professional Training: responsible for the one-year placement programme for BSc students

Formerly Leader of the Soft Matter Group

Research News

We have funding for a PhD student (tuition fees plus £14,000/year for living expenses) to develop polymer colloid coatings for seeds.  The project is sponsored by Syngenta.  To apply send your CV and covering letter to Professor Keddie.

We have recently joined the BARRIER-PLUS project (FP7), and we are now recruiting two post-doctoral researchers: an experimentalist to study film formation and a theorist to model the process.

We have recently moved into refurbished laboratory space.  Have a look on a virtual tour here.  We also have access to a new thermal analysis laboratory shown here.

Our report of a new method to make patterned polymer coatings using IR-assisted evaporative lithography has been highlighted on the inside front cover of Soft Matter. The research was also reported in Eureka magazine and The Engineer. We have also applied for an international patent on the technology.

Professor Keddie's lecture at the Coatings Science International (CoSI) meeting in 2012 won the Innovation Prize.

My PhD student, Robert Gurney, has won a prize for his poster on switchable adhesives, which was presented at the Adhesion '11 meeting, organised by the IOM3.

Research by my former PhD student, Tao Wang, which was carried out in collaboration with the research team of Stefan Bon at the University of Warwick, has recently appeared as the cover article in Soft Matter. The paper shows how nanocomposite particles of clay and polymers can be used to increase the adhesion energy of polymer films.

My 1994 paper on the reduced glass transition temperature in polymer thin films, which was co-authored with Professor Richard Jones (now at the University of Sheffield), has been named as one of the 25 most-cited articles in the Europhysics Letters archive.

Posters by Tecla Weerakkody (Soft Matter PhD student) and Dr. Carolina de las Heras (post-doctoral fellow) won prizes at the UK Polymer Colloids Forum meeting at the University of Greenwich in August 2008.

A paper written by part-time PhD student, Nicki Kessel, and me has won the 2007 Roon Award (Second Place) from the Federation of Societies for Coatings Technology.  Nicki collected the prize (a plaque and a cheque) in Toronto in October.

Our research with Dr. Paul Sellin, which showed that conjugated polymers can be used for the direct detection of X-radiation, has been highlighted in Laser Focus World.

Tecla Weerakkody, a Soft Matter PhD student,  won the BASF Poster Prize at the International Conference on Polymer Colloids, held at the University of Warwick in September 2007.

Mr. Tao Wang, who is a PhD student working with Joe Keddie and Alan Dalton, has won the "Best Student Paper Prize" from the Polymer Physics Group of the Institute of Physics.  Wang presented his prize-winning paper at the Biennial Meeting in Durham in September 2007.

Our recent work on waterborne, nanocomposite adhesives having electrical conductivity and optical clarity has been featured in the  "Spotlight" on the Nanowerk website on nanotechnology news.  This work was also selected by the editors of Science magazine for their "Editor's Choice" column on November 17th 2006.  (The link requires a subscription to Science.) Mark Levine wrote that the properties of our adhesives "bode well for eventual applications of this relatively environmentally benign material in electronics and displays."  Below is a photograph of the de-bonded surface of an adhesive that is a nanocomposite of carbon nanotubes and poly(butyl acrylate). 

Joe Keddie gave an invited lecture at the Tess Award Symposium in honour of Prof. "Skip" Scriven at the 234th ACS Meeting in Boston in August 2007.  He also gave an invited lecture at the European Coatings Symposium in Paris.

Professional Activities

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