Structure and dynamics of tetra-PEG gel by Brownian dynamics

Abstract

We have made coarse-grained model for the tetra-PEG gel and analyzed the gel formation process and the structure of the tetra-PEG gel by using Brownian dynamics simulation. The simulations successfully obtain a reasonable reaction rate with respect to the simulation step. Calculating the number and types of cross-linkings before and after gelation, we found that gelation is caused by monomers with up to three cross-linkings. After gelation, most of the cross-linkings occur in the largest cluster, with cross-linking in the fourth reactive group. By studying mesh structure in the gel after cluster formation, we found the decrease of the size of the loops by cross-linkings. Particularly, loops of size eight were most abundant in our system, which can be one of the reasons for the high strength of the gel.