1. Superabsorbent Hydrogels That Are Robust and Highly Stretchable
- Author
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Robert M. Briber, Dominic Rumore, Stephen J. Banik, Wonseok Hwang, Renu Sharma, Bani H. Cipriano, and Srinivasa R. Raghavan
- Subjects
chemistry.chemical_classification ,Acrylate ,Materials science ,Polymers and Plastics ,Comonomer ,Organic Chemistry ,Ionic bonding ,Polymer ,Inorganic Chemistry ,chemistry.chemical_compound ,Monomer ,Polymerization ,Chemical engineering ,chemistry ,Covalent bond ,Polymer chemistry ,Self-healing hydrogels ,Materials Chemistry - Abstract
Polymer hydrogels synthesized by chemical cross-linking of acrylate or acrylamide monomers can absorb more than 100 times their weight in water. However, such gels are usually fragile and rupture when stretched to moderate strains (∼50%). Many strategies have been developed to create tougher gels, including double-networking, incorporation of nanoparticles as cross-linkers, etc., but these strategies typically retard the water absorbency of the gel. Here, we present a new approach that gives rise to superabsorbent hydrogels having superior mechanical properties. The key to our approach is the self-cross-linking ability of N,N-dimethylacrylamide (DMAA). That is, we conduct a free-radical polymerization of DMAA (along with an ionic comonomer such as sodium acrylate) but without any multifunctional monomers. A hydrogel still forms due to interchain covalent bonds between the growing linear polymer chains. Gels formed by this route can be stretched up to 1350% strain in the unswollen state. The same gels are ...
- Published
- 2014