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Switching the Adhesive State of Catacholic Hydrogels using Phototitration



Evan M. White, Jonathan Seppala, Parker M. Rushworth, Suraj Sharma, Jason Locklin


A polyacrylamide hydrogel system that can be liquefied by remote activation using UV irradiation was investigated as a degradable adhesive. The linear polyacryamide copolymer, formed by conventional free-radical polymerization, contains biomemetic catechol-iron-mediated cross-linkers that are sensitive to pH changes. Hydrogel films and bulk gels were prepared by basic titration of a polymer solution doped with a photoacid generator, diphenyliodonium chloride, generating an ionic cross- linked network via the catechol pendant groups. Irradiation of these hydrogels with UV light affords a viscous liquid solution, demonstrating a gel-sol transition with a subsequent decrease in the adhesive strength of the material. These gels may be prepared in high throughput and require few synthetic steps with commercially available precursors.


White, E. , Seppala, J. , Rushworth, P. , Sharma, S. and Locklin, J. (2013), Switching the Adhesive State of Catacholic Hydrogels using Phototitration, Macromolecules, [online],, (Accessed May 28, 2024)


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Created November 18, 2013, Updated October 12, 2021