Control of TiO₂ Growth Conditions Using Tetrahydropyran Protected Self-Assembled Monolayer and Alkyl Isocyanate

The control of TiO₂ growth condition on tetrahydropyran (THP)–2-carbamate propyl triethoxysilane (TCPES) using thermal heating and octyl isocyanate (OIC) was investigated. TiO₂ can be grown on surfaces terminated with –OH and –NH₂ groups from an aqueous solution of about pH 3. However, TiO₂ did not deposit on the –CH₃ terminated surfaces due to the low surface energy of these surfaces. The –THP functional group can be removed, and the surface functional group can be converted to –NH₂ by heating the material over 200°C. OIC can then be immobilized on the surface after heating, changing the surface functional group from –NH₂ to –CH₃. As TiO₂ can be deposited from a solution on a –NH₂ terminated surface but not a –CH₃ terminated surface, TCPES can be used to switch the surface properties by thermal activation and subsequent reaction with OIC. This approach has the potential to be used for site-selective deposition of TiO₂ on surfaces. ©2010 The Electrochemical Society