Molecular Simulations Integrated Machine Learning Study of Bottlebrush Polymers

Thermosensitive bottlebrush polymers (BBPs) are a type of graft polymers in which thermosensitive polymer side-chains are grafted to a polymer backbone. Most of these thermosensitive polymers with lower critical solution temperature (LCST) can undergo a coil-to-globule conformational transition with increasing temperature. This further results in a change in the overall shape of the BBPs, which is one of the most important properties needed in many biomedical applications including drug delivery, molecular actuators, etc. In this talk, I will discuss our recent coarse-grained (CG) molecular dynamics (MD) simulations study of poly(N-isopropylacrylamide) (PNIPAM; LCST= 305 K) BBPs of three different shapes: 1. Worm-like, 2. Cone-like, and 3. Dumbbell-like. The CG MD simulations were performed at 290 K (below LCST) and 320 K (above LCST) in the presence of explicit CG water for 500 ns. The analysis of simulation trajectories performed using in-house computer codes and data-driven machine-learning methods suggested that the shape of BBPs has significant impact on the conformations of side-chains as compared to other structural features (e.g. grafting density and side-chain length) and temperature.