Self Assembly Of Inverse Opal Hydrogel Photonic Crystals And Its Response To Chemical Substances

The refractive index and lattice of responsive photonic crystals can vary with the change of the external environment,which in turn causes the movement of the photonic band gap.When the photon band gap falls in the visible region,the macroscopic performance of the structural color changes can be used for research and development of visual sensors.Molecular imprinting technique can introduce nano cavities that match the shape,size and binding sites of the imprinted molecules in the polymer,and can achieve specificity detection of target molecules.In this paper,two visual sensors are constructed from the perspective of the responsive photon crystals and its combination with molecular imprinting,and their responsiveness to different chemical substances is studied.A large-area poly-2-hydroxyethyl acrylate inverse-opal hydrogel(IOHG_PHEMA)film with bright color was prepared by a ultrasonic self-assembly method.The IOHG_PHEMAHEMA film responds to a series of water-soluble alcohols and carbonyl compounds.By changing the type of organic compound and the concentration of the chemical,the brightly colored structural color of the IOHG_PHEMAHEMA film can change rapidly throughout the visible region.In addition,IOHG_PHEMAHEMA film can not only be reused,and its response is fast,semiquantitative analysis of chemical concentration variation can be realized on the basis of diffraction wavelength shift.Large area copolymer films of 2-hydroxyethyl methacrylate and phenylboronic acid(IOHG_HEMA+3APBA)were successfully prepared by a capillary force induction method.The responsiveness of the IOHG_HEMA+3APBAEMA+3APBA film to monosaccharides,polysaccharides and polyhydric alcohols was studied by using the combination of phenylboronic acid and polyhydroxy groups in a certain pH range.The reflection peak of the IOHG_HEMA+3APBAEMA+3APBA film shifts to the long wave direction with the increase of the concentration of the detection substance,covering the entire visible region,and the concentration range can be determined by the change of color,and the micro-detection is realized.It is worth mentioning that this chapter also achieves a linear detection of glucose within the physiological concentration range.The inverse opal hydrogel film was prepared by D/L-Ribose as an imprinted molecule,and it could be used for simple and rapid detection of different concentrations of D/L-Ribose aqueous solution.Preparation,responsiveness and mechanical properties of the D-Ri_x-IOHG^w_PHEMAy+AAHEMAy+AA film can be affected by the content of imprinting molecules,AA monomer and crosslinking agent,and D-Ri_0.01-IOHG^3%_{PHEMA0.21+AA0.14}HEMA0.21+AA0.14 film is the final study through the comprehensive adjustment of various factors.The imprinted IOHG_{PHEMA0.21+AA0.14}HEMA0.21+AA0.14 film has a good selectivity for the corresponding imprinting molecules,and when the corresponding imprinting molecules enter the nano cavities in the film,the film swells and causes a red shift of the?_max.The film has good reversibility,physical stability and chemical inertness,and can be recycled several times.