We demonstrate the ability to modulate polyacrylamide hydrogel surface morphology, rheological properties, and adhesion response by combining acrylic acid copolymerization and network confinement via grafting to a surface. Specifically, AFM imaging reveals both micellar and lamellar microphase separations in grafted copolymer hydrogels. Bulk characterization was conducted to reveal the mechanisms underlying microstructural changes and ordering of the polymer network, supporting that they stem from the balance between hydrogen bonding in the substrate-grafted hydrogels, electrostatic interactions, and a decrease in osmotically active charges. The morphological modulation has direct impacts on the spatial distribution of surface stiffness and adhesion. A proof of concept via salt screening demonstrates the dynamic control of surface morphology and adhesion. This work advances the knowledge necessary to design complex hydrogel interfaces that enable spatial and dynamic control of surface morphology and thereby of adhesion through modulation of hydrogel composition and surface confinement, which is of significance for applications in biomedical devices, soft tissue design, soft robotics, and engineered tribosystems.

Surface morphology, rheological response, and adhesion of charge-induced structural changes of confined copolymer hydrogels

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

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