Prediction of physical properties of polymers through hierarchical simulations
Advancing the chemical engineering fundamentals
Keynote Lectures: Theme-2
Keywords: molecular modelling, entanglements in polymer melts, glassy polymers, diffusion in polymers, adhesives
The computational prediction of physical properties of polymers is very challenging, because of the extremely broad spectra of length and time scales governing structure and molecular motion in these materials. This challenge can only be met through the development of hierarchical analysis and simulation strategies consisting of many interconnected levels, each level addressing phenomena over a specific window of time and length scales.
In this lecture we will discuss some examples of new methods and algorithms for the hierarchical modelling of polymers. We will show that connectivity-altering Monte Carlo simulations are capable of equilibrating atomistic models of polymer melts of high molecular weight at all length scales, thereby providing excellent predictions for thermodynamic and conformational properties. For polymers of complex chemical constitution, coarse-graining into model representations cast in terms of fewer degrees of freedom greatly enhances the efficiency of equilibration. We will discuss how topological analysis of atomistic or coarse-grained melt configurations reduces these configurations into entanglement networks suitable for mesoscopic simulations of deformation and flow. For glassy polymers, we will see how the idea that a glass is confined in the vicinity of local minima in its configuration space can be used to estimate volumetric properties and elastic constants, and to model long-time physical ageing and plastic deformation phenomena as sequences of transitions between such minima. We will outline how the diffusivities of gas molecules through glassy polymers can be estimated through multidimensional transition-state theory. Finally, we will see how self-consistent field calculations coupled with rubber elasticity theory can be used to address the complex morphology and stress-strain behaviour of multicomponent block copolymer-based materials, such as pressure sensitive adhesives.
Presented Monday 17, 17:05 to 17:45, in session Keynote Lectures: Theme-2 (T2-K1).
