Fig. 2: Colloidal hydrogel fabrication using the sacrificial scaffold.

a Chemical structure of the reagents used. b Optical and SEM images of the (i) sacrificial scaffold, (ii) secondary polymerized hydrogel, and (iii) hydrogel after degradation. Scale bars: 2 mm for optical images and 500 nm for SEM images. c Normalized reflection spectra of the hydrogels in b. d Raman spectrum of the PEGDA hydrogel (fabricated without sacrificial scaffold), and the hydrogels in b. e Schematic demonstration of the formation of patterned PEGDA colloidal crystal hydrogel using a sacrificial scaffold, and the photo of the hydrogels obtained during the fabrication process. Scale bars: 5 mm.