Modulation of spatial and topological inhomogeneities of linear polymer hydrogel

It is well known that physical properties such as optical transparency, mechanical strength and permeability of hydrogel are strongly related to inhomogeneities of hydrogel. The physical properties of hydrogel, including inhomogeneity, are affected by the polymer volume fraction and amount of crosslinker at the state of hydrogel preparation typically. To study the influence of polymer volume fraction and amount of crosslinker on the inhomogeneities of linear polymer hydrogel, molecular dynamics simulation is performed to reproduce gelation process and quantified inhomogeneities of the obtained hydrogel network. Furthermore, the generation and variation mechanisms of inhomogeneities in linear polymer hydrogel are revealed through investigation of crosslink pattern and formation and collapse of cluster. The results indicate that increase of the polymer volume fraction and decrease of amount of crosslinker can increase the spatial inhomogeneity of the hydrogel. The topological inhomogeneity increases almost monotonically with polymer volume fraction, but first increases and then decreases with the increase of the amount of crosslinker. It is concluded that inhomogeneities of linear polymer hydrogel can be flexibly modulated by polymer volume fraction and amount of crosslinker.