(521c) Accessing Phase Behavior of Block Copolymer Grafted Nanoparticles Using Coarse-Grained Simulations and Protracted Colored Noise Dynamics

Nanoparticles may be added to polymers to improve mechanical, thermal, or optical properties of the resulting nanocomposite, but fine control over nanoparticle arrangement and interfacial state is necessary for these systems to reach their ultimate potential. By grafting block copolymers to nanoparticles, precise arrangement of nanoparticle may be achieved. However, the study of long range behavior of such system via simulation is difficult because significant time and length scales are required. By combining a coarse-grained model with a technique called protracted colored noise dynamics (PCND), sufficient sampling can be achieved. PCND applies a random force that is correlated through time and space to increase sampling over large energy barriers and increase diffusivity. Spatial correlations consistent with major modes of diffusion have been shown in increase sampling of rare events in linear polymer samples by over 4 orders of magnitude. Application to block copolymer grafted nanoparticles results in access to equilibrium and dynamic properties. Behavior is studied as a function of graft length vs. particle size and of the volume fraction of each block within the grafts.