Solvent-assisted poly(vinyl alcohol) gelated crystalline colloidal array photonic crystals

We have prepared a solvent-assisted poly(vinyl alcohol) (PVA) gelated crystalline colloidal array (GCCA) photonic crystal material. PVA GCCA was formed by utilizing a well-known freeze-thawing method while the crystalline colloidal array (CCA) was physically immobilized within the PVA hydrogel network. This photonic crystal material could be conveniently fabricated, shaped as needed and efficiently diffracts visible light. The diffraction wavelength can be tuned anywhere within the visible spectrum by simply varying the CCA concentration or stretching the sample. The GCCA demonstrated sol–gel reversible behaviour as the temperature was cycled. It has been observed that the GCCA maintained its ability of diffraction after rehydration, and the sample could be stored for long periods of time at room temperature.