Viscoelastic Properties of Polymer Systems From Dissipative Particle Dynamics Simulations

摘要

The U.S. Army has an increasing need for multifunctional polymers with specific viscoelastic properties. Such polymers are often present in nanocomposites, lubricants, or biomimetic gels that are used as tissue surrogate materials. Rational prediction of a polymer's viscoelastic properties necessitates the use of multiscale modeling since vastly different time and length scales have to be considered. In this study, we will apply the dissipative particle dynamics (DPD) method that is a fast and accurate alternative to traditional molecular simulations. The DPD method is a particle- based, coarse-grained mesoscale method. In this study, the simulation of viscoelastic properties is carried out by applying an additional, oscillatory shearing force. This oscillatory shear and corresponding stress allows us to calculate the storage (G') and loss modulus (G') that define the viscoelastic behavior of polymer systems. As a demonstration exercise, the G' and G' moduli were calculated for a diblock copolymer at low frequencies.