Figure 1. Proposed mechanism, photographs, and SEM and TEM images of the functional ZnO-NC hydrogel.

(a–c) Proposed mechanism of the functional NC hydrogels under sunlight. The semiconductor NPs, monomer, and Clay-NS are homogeneously dispersed in water (a). When exposed to sunlight, polymerization is initiated by the semiconductor NPs (b). Next, the NPs and Clay-NS are cross-linked to develop a 3D network (c). (d–f) Optical images of the hydrogelation process. A mixture solution of ZnO nanoparticles, DMAA, and Clay-NS (d). Hydrogelation after 1 h of irradiation (e). The elastic ZnO-NC hydrogel (f). (g) SEM image of the ZnO-NC hydrogel after supercritical drying. (h) TEM image of the ZnO-NC hydrogel after a bio-cutting treatment.