Developing coarse-grained force fields for PNIPAM single chain from the atomistic model

A coarse-grained (CG) model of Poly (N-isopropylacryl-amide) (PNIPAM, a kind of thermo-sensitive polymer with widely application) single chain at high temperature is developed from atomistic simulation using Iterative Boltzmann Inversion (IBI) method. The specified structural property of PNIPAM is well represented using this CG single chain model. But we find that this model cannot apply to lower temperature. We analyze the temperature effect on this CG model and some limitations of the IBI method. The results show the extensibility in wide temperature applicability of this model need to be improved.