Nanoscale Structure and Mechanical Properties of Cross-Linked Hydrogels

Recently, hydrogels have been employed in a variety of engineering applications as promising materials, since their porous structure and hydrophilicity enables them to absorb a large amount of water. Atomistic simulations lead to a better understanding of their properties at nanoscale, especially mechanical properties. In this study, hydrogel is studied using a molecular dynamics (MD) framework, considering condensed phased optimized molecular potential (COMPASS) as the force field. Polyethylene glycol diglycidyl ether (PEDGE) and poly-oxy-alkylene-amines (Jeffamine) are the epoxy and curing agent used for hydrogels, and a novel cross-linking method is applied. Radial Distribution Functions (RDFs) show that the cross-links are the hydrophilic part of hydrogel. RDFs and mechanical properties are reported for different water amounts. The results show that an increase in water content leads to a decrease in elastic modulus of the hydrogel.