Due to the facility of produce process and having properties of both organic and inorganic, sol-gel hybrid materials which organic groups are introduced into inorganic network have wide application. The organic part of hybrid materials has the similar properties of general polymer under UV irradiation such as photo induced polymerization of unsaturated double bond by free radicals, photodecomposition and photolocking of new dopants or molecules. Photolocking is used in polymer materials in which the refractive index and thickness of a thin polymer film is selsctively increased by photochemical reaction. In new molecules doped hybrid materials, surface deforming is found under selectively UV exposure and produce of variable patterns is possible.
In this study, the solution of hydrolytic sol-gel method and non-hydrolytic sol method used to produce thin film of photo sensitive and photo-patternable hybrid inorganic-organic polymeric glass on silicon. Glasses that consist of photoinitiator, methacryloxypropyltrimethoxysilae (MPTMS), methacrylic acid, zirconium propoxide(ZPO) and perfluorodecyltrimethoxyslane (PFAS) are suitable to study photochemical reactions and patterning.
Because of cooking sol-gel solution without water, non-hydrolytic sol-gel hybrid material has very low silanol group (Si-OH) , which is one of major reasons main cause of optical loss. And the problems that crack of film or volume shrinkage by evaporation of solvent were found under thermal curing could be avoided. The starting precursors of MD were methacryloxyprolpyl-trimethoxysilane (MPTMS) and diphenyl silanediol (DPSD).
In both MFZ and MD system, the methacrylate groups of MPTMS was photochemically reacted under UV irradiation. The photosensitive dopants are benzildimethylketal (BDK) and 1-hydroxy-cyclohexylphenylketone (HCPK).
Photochemical reactions were expected through the refractive indices changes with dopant concentration, UV irradiation and UV source type. Through using photo-differential scanning calorimetry (DSC), photopolymerization of inorganic-organic hybrid material was confirmed. The photodecompositions of organic part with variable UV sources were confirmed by UV-spectrophotometer. The structure change of dopant in photolocking process were investigated by FT-IR spectroscopy. Finally, the patterned images of sol-gel hybrid materials using photochemical reactions were confirmed by optical microscopy and AFM(atomic force microscope).
