Polymer networks

The submersion of a polymer network with a high density of hydrogen bond based cross-links in an aqueous bath results in the formation of a rubber-like hydrogel. The cross-links, which connect chains and maintain the structure of the network, can dissociate as a result of two main factors: (1) the interactions between the hydrogen bonds and the surrounding water molecules and (2) the forces that are exerted on the cross-link from the interconnected chains.

JMPS link: https://www.sciencedirect.com/science/article/pii/S0022509619304405?dgcid=raven_sd_aip_email

Arxiv link to full text: https://arxiv.org/abs/1905.08485

An Adaptive Quasi-Continuum Approach for Modeling Fracture in Networked Materials: Application to Modeling of Polymer Networks

Our recent work introduces a microscopically motivated model for the swelling response of polymer networks with non-covalent cross-linking bonds.

As opposed to the classical theories of rubber, we show that the uptake of water in polymer networks comprising hydrogen cross-linking bonds can lead to the dissociation of cross-links. This phenomenon leads to a reduction in the chain-density, an increase in entropy, and a decrease in the free energy.  As a result, the network experiences significant softening and exhibits a different mechanical response.

Link: https://www.sciencedirect.com/science/article/pii/S0020768319303063?via%3Dihub

Highlights:

Preprint here: https://www.researchgate.net/publication/333260238_An_Adaptive_Quasi-Co…

Mechanical Response of Two Dimensional Polymer Networks: Role of Topology, Rate Dependence, and Damage Accumulation