Photonic Crystal In The Applied Research Of Ecological Environment Monitoring

The environmental gas monitor system is a vital target for the environmental ecology work, as the whole society focus increasingly on air quality, that how can we timely monitor the harmful gases contained in the environment in an effective way, has continuingly been greatly concerned by the people.The multifunctional and responsive photonic crystals (PCs) have extensive and promising applications in environmental monitoring, and physical, chemical and biological sensing. This dissertation focuses on the fabrication of PCs with good optical properties; highly sensitive and reusable acid-base vapors responsive polyaniline (PANI)-TiO2composite inverse opal photonic crystals; highly sensitive and reusable acid-base vapors responsive PANI-TiO21DPCs. The main contents are the following:1) The fabrication of3D PS polystyrene colloidal PCs via a vertical deposition method. The opal templates were obtained by assembling a latex suspension of polystyrene (PS), synthesized by a series of designed synthetic experiments. This vertical deposition fabrication procedure and the latex suspension of polystyrene synthetic experiments will be of great significance for extensive applications of PCs in the fields of optic devices and functional coatings, etc.2) The acid-base vapor responsive PANI-TiO2composite inverse opal photonic crystals were fabricated. The reversible change of PCs’reflectance spectra can be obtained when the as-prepared PCs is switched from the acidic to basic vapor environment, where PANI can be dopped or dedopped and leads to the correspondingly variation of the effective reflective index of the PC film. At saturated NH3environment, the stopband of PANI-TiO2inverse opal changes from556nm to688nm, as such a shift as large as132nm can be observed. Correspondingly, the color of film rapidly changed from green to red. After placing in an HCl environment, the stopband had a blue shift and the color turned from red to green. The detection by naked eye of NH3and HCl vaopr can be realized by reversible color change of the PCs film, which is very important for chemical and biological sensors.3) The acid-base vapor responsive PANI-TiO2ID photonic crystals were fabricated. The reversible change of PCs’reflectance spectra can be obtained when the as-prepared PCs is switched from the acidic to basic vapor environment, where PANI can be dopped or dedopped and leads to the correspondingly variation of the effective reflective index of the PC film. At saturated HCl environment, the stopband of PANI-TiO21DPCs changes from517nm to635nm, as such a shift as large as118nm can be observed. Correspondingly, the color of film rapidly changed from yellowgreen to orange. After placing in an NH3environment, the stopband had a blue shift and the color turned from orange to yellowgreen. The detection by naked eye of HC1and NH3vaopr can be realized by reversible color change of the PCs film, which is very important for chemical and biological sensors.