2022 Volume 35 Issue 4 Pages 321-326
In this report, we successfully fabricated the temperature-responsive porous gel film by templating the colloidal crystal (CC) film of silica microparticles embedded in a hydrogel matrix of poly(N-isopropylacrylamide) (NIPA). As elevating the temperature from 25 ℃, this porous gel film showed the color changes of Bragg reflection from red to blue, arising from the geometric decrease in the lattice spacing of pores caused by the shrinkage of NIPA gel matrix upon heating process. Such reflection color changes of the porous gel film were found to be fully reversible in the temperature range between 26 ℃ and 33 ℃. Moreover, Fourier transform infrared (FT-IR) spectroscopy and thermal gravimetric analysis (TGA) measurements suggested that the silica microparticles of CC film are thoroughly removed after treatment with hydrofluoric acid, thereby resulting in the formation of porous NIPA gel film without the silica component. This report provides a promising protocol to check the residual silica microparticles in porous gel films by both FT-IR and TGA measurements.
