A facile method to assemble PNIPAM-containing microgel photonic crystals

Structural colors: Poly(N-isopropyl acrylamide) based microgel photonic crystals are fabricated by using a new method called "high-temperature-induced hydrophobic assembly". The assembling conditions affect the water content of the crystals, thus determining their structural color (see image). The obtained photonic crystals are sensitive to solvents, and the reversible changes in their color can be observed with the naked eye.