(131e) Computational Design of Feather-like 2-D Polymer Architectures

Inspired by the shape of birds’ feathers, we have computationally designed a new class of two-dimensional (2D) branched polymers called feather-like polymers. Similar to feathers, these polymers have branched architectures consisting of polymeric side chains (barbs) attached to a central polymeric backbone (rachis) such that they remain in one plane. We used coarse-grained (CG) molecular dynamics (MD) simulations to design and investigate structural and solvation behavior of feather-like polymers consisting of side chains of a thermo-sensitive polymer, poly(N-isopropylacrylamide) (PNIPAM). PNIPAM has a lower critical solution temperature (LCST) below and above which, it shows a coil-like and globule-like structure, respectively. Specifically, we investigated the effect of temperature as well as structural characteristics such as grafting density, side chain length, and adding chemical cross-links between adjacent side chains on the conformation of the polymers and the planarity of the side chains. We show that increasing grafting density and side chain length cause the feather-like polymers to retain their 2D structure. Moreover, introducing cross-links between adjacent side chains results in a larger end-to-end distance and in-plane side chains. Thus, retaining 2D structure of feather-like polymers. In addition, our comparison between 2D feather-like polymers and 3D bottlebrush polymers shows that at 300 K which is below LCST of PNIPAM, solvent accessible surface area (SASA) of 2D feather-like polymers is smaller than that of 3D bottlebrush. However, at 320 K, due to the hydrophobic nature of PNIPAM at temperatures above LCST, less planarity of side chains was observed which resulted in larger SASA values. This study provides guidelines for creating a novel class of 2D polymers, and has the potential to open a new area of research in 2D branched architectures.