Computational Modeling of Polymer Melts and Composites

Download or read book Computational Modeling of Polymer Melts and Composites written by Shaghayegh Khani and published by . This book was released on 2017 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Past decades have experienced a plethora of computational studies and with the recent advancements in the computing power; such studies can sometimes be even more efficient than running an experiment in a Laboratory. Computer simulations in molecular scales are performed to bridge the gap between theoretical studies and experiments. Dissipative Particle Dynamics (DPD) which is essentially a Coarse-Grained particle based technique is one of the most promising computer simulation methods in the meso-scales. In DPD each particle represents a group of atoms that are lumped together. Tuning the interaction potential between the particles allows capturing the chemical and physical properties of different types of systems. In this thesis, we first explain the fundamentals of the simulation method, then DPD is used to model polymers and composites. In the first chapter, we focus on the effect of the thermostating technique on proper reproduction of the dynamics of polymer melts. This chapter is followed by a pure DPD investigation of linear viscoelastic properties of polymer chains in entangled and un-entangled regimes. More specifically we will modify the model in order to capture the Rouse to Reptation transition due to the entanglements. A systematic study of the deterministic factors for morphology developments in mixtures of polymers with bare and chemically modified nano-rods is presented in chapter three. A three dimensional phase diagram that includes the effect of both enthalpic and entopic effects is mapped for nano-rod dispersion/aggregation in a polymer matrix. In chapter four, with an inspiration from nature we propose a model for capturing the stimuli responsive behavior of a specific polymer system. Thermo-responsive polymer composites are computationally modeled using an extension of DPD with energy conservation capability. The final chapter of the thesis presents a preliminary study on the interfacial arrangement of double-faced "Janus" particles. Interfacial arrangement of Janus particles is found to be crucial for modifying the morphology and properties of multi-phase systems. Thus in the last chapter of this thesis we briefly study the effect of interface properties and the particle characteristics on their interfacial self-assembly.