Coarse-Grained Molecular Dynamics Simulations of PNIPAM Grafted Graphene Systems in an Aqueous Environment

Individually, graphene nanostructures and the thermo-sensitive polymer Poly(N-isopropylacrylamide) (PNIPAM) have shown the potential to aid in drug delivery applications.  A viable drug delivery vehicle will likely take the form of a macromolecule consisting of a graphene architecture functionalized with PNIPAM chains.  Designing a delivery vehicle will require a detailed understanding of how such a structure behaves in an aqueous environment.  All-atom Molecular Dynamics (MD) simulations have been conducted on systems comprised of a PNIPAM chain 30 monomer units in length and a graphene sheet measuring up to 40 Å by 40 Å in the presence of water.  These initial simulations have already required moderate computational time at the traditional all-atom MD time scale.  Coarse-graining of graphene, PNIPAM, and water is required if a macromolecule-water system is to be studied on a time scale representative of a biological system.  In this work, we have employed Particle Swarm Optimization (PSO) and traditional coarse-graining techniques to develop a model that was utilized to examine graphene and PNIPAM architectures in an aqueous environment.