Fig. 2.

The preparation and characterization of structured colored hydrogel patches (NNH film). a) The manufacturing processes. Schematic diagram (Top) and SEM image (Bottom) of the fabrication process. From left to right: (i) silica colloidal crystal templates (SCCs), (ii) the colloidal crystal template after the penetration of hydrogel (Hybrid film), (iii) the inverse opals, (iv) inverse opals with hydrogel filled. b) Deformations of NNH patch. The chemical structures of the c) PNAGZ and d) PNIPAM. The scale bars are 200 nm in a, and 1 cm in b.