Engelhard titanosilicate ETS-10 has attracted much interest for photocatalytic applications due to its monatomic semiconductor …-Ti-O-Ti-O-Ti-… chains and its band gap energy of 4.3 eV. Preparation of ETS-10 films on nonporous GaAs substrates was investigated using gel-forming synthesis mixtures with molar composition 5.2Na2O : 0.5K2O : 1.0TiO2 : 5.5SiO2 : 113H2O, and initial pH≈10.5. Hydrothermal syntheses of ETS-10 in the presence of the GaAs substrates were carried out at 503 K for 2-6 days. After 2-day synthesis, very few ETS-10 crystals appeared to be electrostatically attached onto the GaAs substrates, with the bulk product being fully crystalline. After 6-day synthesis, the same amount of crystals appeared to be present on the substrate as after 2-day synthesis. This indicated that direct hydrothermal synthesis was not the route to consider in ETS-10 film growth on GaAs. Use of covalent linkers in the supported zeolite and zeotype film growth has been investigated by several groups. Yoon et al. [1] proposed that binding of zeolite A crystals onto XP-coated (where P is propylsilyl, and X is: C for chloro, B for bromo, or I for iodo) glass plates proceeded via direct nucelophilic substitution of the terminal halide in the glass-bound XP groups by the hydroxyl groups located on the zeolite A external crystal surface. In order for covalent linkage to occur, the CP and the hydroxyl groups on the glass plate and zeolite, respectively, must be present, as shown by the following schematic 1, where G is the glass substrate, and Z is zeolite A: Utilizing this methodology of covalent linkers a polysiloxane photoconductive polymer was used to coat non-porous substrates, and then ETS-10 crystals were attached via refluxing, or using a dip coating technique. In order to utilize a similar method to that of Yoon et al. [1]and increase the coverage of the film, modification of ETS-10 might be necessary in order to increase the number of terminal hydroxyl groups. Several groups investigated post treatment using acids to modify the ETS-10 crystal structure, which enhances the photocatalytic activity of ETS-10 due to the increase in the amount of TiOH sites created during the acid treatment [2]. Lv et al. [3] found that acid treatment changes the octahedral titanium to penta- and/or tetra-coordinated titanium, and generates terminal TiOH groups. This enhances the photocatalytic activity of ETS-10. Therefore, it can be hypothesized that acid treatment may be beneficial not only for photocatalysis, but also for formation of intact ETS-10 films. Preliminary results on glass substrates will be presented. [1] Kwang Ha, Yun-Jo Lee, Han Ju Lee, Kyung Byung Yoon, Adv. Mater. 2000, 12, No. 15, 1114. [2] Llabrexsi Xamena, F. X., Calza, P., Lamberti, C., Prestipino, C., Damin, A., Bordiga, S., Pelizzetti, E., Zecchina, A. J. Am. Chem. Soc. 2003,125, 2264. [3] L. Lv, J. K. Zhou, F. Su, X. S. Zhao, J. Phys. Chem. C 2007, 111, 773-778.