Research On Robust Photonic Crystal Films

Photonic crystal films were successfully prepared by embedding polystyrene crystalline colloidal arrays (CCA) in the P(HEMA-co-AM) or PAM/PEG2000 hydrogel. The films were characterized by FTIR and UV-Vis Reflectance Spectrometer. FTIR shows that comonomer hydroxyethyl methacrylate (HEMA) and polyethyleneglycol (PEG2000) are introduced successfully into polyacrylamide photonic crystal film. The reflectance spectra indicate that the ordered structure of CCA is embeded in the hydrogel and the stopband is located in the visible spectrum region.The tensile test indicates that the mechanical properties of P(HEMA-co-AM) and PAM/PEG2000 films are better than that of pure polyacrylamide film. Compared to P(HEMA-co-AM) film, the mechanical property of PAM/PEG2000 film is good.The sensitivity to solvent and pressure was also studied. With an increase in the concentration of ethanol in water, the stopband of both photonic stopband films blue-shifts because of the decrease in solubility parameter of solvent mixture; The photonic stopband blue shifts linearly and reversibly on compression. The response time is very short, within several seconds. The photonic stopband films can be used as ethanol detector or pressure sensors.