Computational Design of Bottlebrushes of PNIPAM-Dextran Copolymers

In the present study, we have performed coarse-grained (CG) molecular dynamics (MD) simulations of bottlebrush polymers (BBPs) of dextran and poly(N-isopropylacrylamide) (PNIPAM) copolymers. PNIPAM is a thermosensitive polymer with a lower critical solution temperature (LCST) of 305 K, below and above which it is soluble and insoluble in water, respectively. Dextran is a water-soluble, biodegradable neutral bacterial exopolysaccharide consisting of repeating glucose subunits. PNIPAM-dextran copolymers and their star-like architectures have already shown potential for various biomedical applications including universal platform for drug delivery. The worm-like and cone-like BBPs of PNIPAM-dextran copolymers with variations in the lengths of PNIPAM and dextran in side-chains and their grafting densities on the BBP backbone were generated. The CG MD simulations of these BBPs were performed below and above LCST of PNIPAM. The analysis of CG MD trajectories performed by using data driven machine-learning (ML) methods to unravel the dependence of metastable states on the side-chain length, grafting density, and temperature. Our research provides guidance in designing novel BBPs of PNIPAM-Dextran Copolymers.