A Molecular View: the Mechanical Behavior of Polymer Networks

Crosslinked polymer networks swollen in solvent, such as hydrogels, have gained much attention for their unique structural and mechanical properties that mimic natural materials and biological tissues. Since the network structure is linked to material properties, it is important to understand the dynamic behavior of the network during mechanical deformation. As many synthetic and natural soft materials are highly inhomogeneous, an important step is to elucidate how structural heterogeneities, such as network defects and phase boundaries, affect the response of the network to deformation. We use coarse-grained molecular dynamics to investigate the response of swollen polymer networks to deformation and the influence of network heterogeneities on the response. We examine the influence of network structures on soft materials’ bulk mechanical properties using tensile deformation to study both reversible and irreversible responses in gels as a function of polymer concentration, strand length, and network defects. We find that the network formation process will dictate local network structure, which is highly correlated to the dynamic material response under deformation.