MoS2-Embedded, Interpenetrating Network Composite Hydrogels that Show Controlled Release of Dyes and Tunable Strength.

This paper describes a conceptual design of hierarchical composite hydrogels. The hydrogel materials comprise MoS2 flakes and interpenetrating polymer networks, and further exhibit controlled release and tunable strength that are caused by the synergistic combination of select components. In terms of design, MoS2 flakes initiate radical polymerization of chosen monomers and simultaneously provide physical cross-linking points, both of which afford a primary composite network. Then, the sequential formation of additional networks results in functional, hierarchical, composite hydrogels. Therefore, we were able to demonstrate double-network hydrogels as a stimuli-responsive vector for programmed release of cargo molecules in response to heat or light or to form triple-network hydrogels showing tunable mechanical strength owing to intermolecular interaction between charged monomers and MoS2 flakes. The design concept would be expanded by incorporating other chalcogenides or functional monomers, which advance the properties and functionalities of materials and broadens the versatility of nanocomposite hydrogels.