Princeton researchers have created a new type of hydrogel that is recyclable, yet still tough and stable enough for practical use (and reuse). The research is explained in a paper that was published Sept. 21 in the Journal of the American Chemical Society Au. 

The study’s lead author, Xiaohui Xu, a postdoctoral researcher, previously worked with hydrogels for use in water purification and wondered if she could create a more environmentally sustainable hydrogel. Xu and her colleagues took a new approach to building hydrogels. Rather than relying on chemical bonds to connect different polymers, the researchers decided to harness phase separation, a familiar phenomenon in which mixed liquids, such as oil and water, separate into components.

“Hydrogels offer tremendous societal benefit, but their lack of sustainability has loomed as a significant issue,” said Xu, a postdoctoral researcher in the lab of Rodney Priestley, the Pomeroy and Betty Perry Smith Professor of Chemical and Biological Engineering at Princeton. “In this study, we have shown how taking advantage of phase separation can lead to new kinds of hydrogels that are durable and recyclable and still have good mechanical properties.”

With additional testing and development, the novel material could make existing and emerging applications for hydrogels — such as artificial muscles and soft robots for safe operation around humans — more sustainable and environmentally friendly.