Many aspects of the dynamic wetting problem have been haunting researchers over the last 40 years due to various paradoxes which appear in macroscopic modelling of this problem. Our recent studies of the moving contact-line problem via molecular dynamics simulations have shown that the dynamic contact angle effect Lukyanov, Likhtman is essentially conditioned by the microscopic processes in a small region, several atoms wide, around the contact line, basically at nanoscale.
We are interested in microscopic modelling of the processes taking place at moving contact lines to understand the origin of the dynamic wetting effects in situations involving simple and complex interfaces, e.
The modern drive towards miniaturization and nanotechnology raises the importance of interfacial science to a new level. Due to widespread of microfluidic applications, the flows during their operation become more and more dominated by the effects of capillarity. This presents an opportunity to control and fine tune various micro-flows by manipulating interfacial properties via the creation of complex interfaces. On the other hand, this calls for detailed theoretical analysis of structure and dynamics of such interfaces in strongly non-equilibrium conditions.
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We study such dynamic interfacial processes in our group from the first microscopic principles, using large scale molecular dynamics simulations. The viscosity of dipolar colloidal fluids ferrofluids can be manipulated by varying an external magnetic field. Current constitutive models suffer from the lack of knowledge about the relevant microstructure. Our simulations provide information on the field- and flow-induced structural changes and will allow us to formulate improved constitutive equations for dipolar colloidal fluids. When magnetic particles are brought into polymer gels, their soft solid-like behaviour responds strongly to external fields.
From a theoretical point of view, the coupling of the translational and rotational dynamics of the magnetic particles to the polymer matrix is largely unknown. From detailed microscopic simulations we want to extract information on how to modify the classical Brownian Dynamics of the particles when they move not through a simple liquid but through a viscoelastic environment.
The viscosity of liquids increases enormously when cooled down towards the glass transition without apparent change of their microstructure.
By analysing the underlying potential energy landscape of a binary Lennard-Jones system, we identify cooperative rearranging regions that grow in size upon cooling. Our simulation results help to improve and provide a microscopic basis of current theories of the dynamics and rheology of glassy systems. Polymer brushes are very effective in lubricating surfaces.
We use nonequilibrium Molecular Dynamics simulations in order to investigate the effect of semi-flexibility as well as different polymer architectures on the resulting coefficient of friction of the polymer-coated surface.
Institute of Physical Chemistry and Polymer Physics
Fluid-fluid interfaces can be stabilized by adsorbed multi-block copolymers that self-assemble into complex microstructures. The influence of the microstructure on the stability and surface rheology we study with a multi-scale approach, combining molecular simulations and nonequilibrium thermodynamics modelling. Charged polymers are abundant both in nature, such as DNA and proteins, and in synthesized materials.
The study of charged polymers is not only inspired by the rich physical properties and so numerous applications resulted from the long-range Coulombic interactions among charged groups, but also the understanding of the functioning of biological systems. Our researches in this direction are focused on theoretical and computational modelling of the conformational transition of diblock polyampholyte chains and the self-assembly behaviour of charged block copolymers and mixtures of oppositely charged polyelectrolytes. Thesestudies are related to the DNA and protein association.
Colloidal dipolar fluids, such as ferrofluids, electrorheological ER and magnetorheological MR fluids, are composed of magnetic particles of nano- to micrometer sizes suspended in carrier liquids. Their magnetic, structural and rheological properties are reversibly tunable by the application of magnetic field. We study the field-induced physical properties of these fluids using computer simulations and theoretical modelling.
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Special attentions are paid to effectively handling the long-range dipole-dipole interactions among magnetic particles. Molecular dynamics simulations at the atomistic level can provide microscopic understanding of physical properties of soft matter materials that are generally hard to achieve in experiments.
This type of simulations also constructs the basis for developing more coarse-grained computational models. The systems we are working on include polymer melts, surfactant micelles, polymer-drug conjugates, etc. The simulation results are directly compared with experimental measurements and contribute to the development of coarse-grained models in the group. Monte Carlo field-theoretic simulation is a novel and very promising technique for studying the fluctuation effects in block copolymers.
In opposite to the chain-based simulation methods, the field-theoretic approach allows to consider very large polymerisation indexes. Mathematically, the technique is related to the well-known self-consisted field theory, but instead of using the mean-field approximation, it exactly describes the composition fluctuations, which are particularly important in the proximity of the order-disorder transition and in the disordered phase.click here
127 polymer-physics positions
We focus on the fluctuation corrections to the mean-field predictions for the disordered-state structure factor and the order-disorder transition in a symmetric diblock-copolymer melt. Recent articles.
Our aim is to provide for all of us the chance to engage with the different research projects going on and to stimulate discussions and new ideas. Therefore, we want this seminar to be informal and lively, with the emphasis on explaining ideas, plans and problems. Richard Graham, University of Nottingham Modelling entangled polymers under flow: recent observations and analytic results.
Polymer Physics Group
University of Reading. Site navigation Page menu Search. Life Open days Accommodation Our campus Reading town. Research Postgraduate Research subject areas. Areas Current students Staff Alumni. Complex Fluids and Theoretical Polymer Physics. The Complex Fluids and Theoretical Polymer Physics group focuses on the structure and dynamics of complex fluids, with polymeric fluids being the overarching theme.
Czuprynski , and S. Roland , A. Ellis , A. Randall , and C. Roland , J. Czub , and S. Prevosto , S. Capaccioli , and C. Twigg , K. Nugent , D.
Lin , P. Mott , C. Robertson , M. Vukmir , T H. Epps, III , and C. Bogoslovov , and C. Ngai , and C. Twigg , Y. Vu , and P. Casalini , " Dynamics of Polycyclohexylmethacrylate, Neat and in Blends with Poly a-methylstyrene ", Macromolecules , vol. Roland , and S. Roland , and R. Maslanka , J. Ziolo , M. Paluch , K. McGrath , and C. Wang , and R.