There has been great interest in designing water-soluble polymeric networks that rely on dynamic non-covalent (supramolecular) processes, with a strong emphasis in the current literature focusing on utilizing host-guest or donor-acceptor interactions as the cross links. Supramolecular cross-linked networks are of particular interest due to the unique physical properties that they possess over traditional covalently linked networks, as the cross links that connect the network can be reversibly broken and reformed, i.e., self-healing. Here we present the synthesis and full characterization of water-soluble unimolecular main-chain viologen copolymers incorporated into a stimuli-responsive non-covalently cross-linked hydrogel network comprising of donor-acceptor interactions between viologens and electron-rich donor moieties. The aforementioned supramolecular cross-linked hydrogels exhibit a dual nature in that they can capitalize on the facile redox chemistry of viologens to undergo substantial physical transformations as a result of generating viologen radical cations, which can undergo radical-based self-assembly to form a different connectivity in the network. This redox-based transition results in the dissolution of the original donor-acceptor cross-linked hydrogel network to form a second distinct hydrogel network based on viologen radical-radical interactions between each viologen subunit in the network. The unique rheological and self-healing properties of each hydrogel are investigated, as well as their electrochemical properties.

Redox-to-donor-acceptor interconversion of supramolecular hydrogels

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.