Response of photonic crystal hydrogels to carbohydrate and polyhydroxy alcohols

Inverse opal hydrogel films composed of hydroxyethyl 2-methacrylate and phenylboronic acid (IOHG(HEMA+3APBA)) were prepared by a convenient ultrasonic-induced self-assembly method. The IOHG(HEMA+3APBA) films had brilliant blue-violet color when they were immersed in deionized water and reached swelling equilibrium. The IOHG(HEMA+3APBA) films were used as sensors to detect chemicals with similar structures. When the IOHG(HEMA+3APBA) films were in contact with different monosaccharide, polysaccharide or polyhydric alcohol solutions, their reflection peaks maxima (lambda(max)) shifted over the entire visible wavelength range (520 to 780 nm). The red shift of lambda(max) was related to the number of effective hydroxyl groups and the molecular size of the detected molecules. Thus isomers or organic compounds with similar structures or properties may induce different lambda(max) shifts of the IOHG(HEMA+3APBA) films.