| We investigated thin films of 3-aminopropyltriethoxysilane (APS), 3-glycidoxypropyltrimethoxysilane (GPS), 3-methacryloxypropyltrimethoxysilane (TPM), trimethoxyvinylsilane (VS), tetraethoxysilane (TEOS), 3-bromopropyltrimethoxysilane (BPS), and 3-mercaptopropyltrimethoxysilane (MPS) adsorbed on aluminum or gold substrates with reflection-absorption infrared spectroscopy (RAIR), optical ellipsometry, wetting measurements, and by gravimetric analysis with the quartz-crystal microbalance (QCM). We present optical response functions in the infrared region and simulations of isotropic RAIR-spectra of these compounds.; Thin films were prepared by vapor adsorption of the silane on the substrate. RAIR-spectroscopy, ellipsometry, gravimetric analysis, and wetting behavior results are consistent with approximately monolayer coverage and a preferential orientation of the molecules on the surface. The adsorption and the final surface loading levels, varying from 3 to 7 molecules per nm{dollar}sp2{dollar}, are affected by the hydrolysis and condensation reactions of the siloxane moieties, as indicated by gravimetric analysis.; We studied the reactivity of thin layers of APS, MPS, BPS, and 8-bromooctyltrimethoxysilane (BOS). We observed stoichiometric reactions of APS with chlorodimethylsilane and of MPS with phenylmercuryhydroxide to give {dollar}rmlbrack -Si(CHsb2)sb3NHsbsp{lcub}2{rcub}{lcub}+{rcub}SiMesb2Hrbrack Clsp-{dollar} and {dollar}rmlbrack -Si(CHsb2)sb3SHgPhrbrack{dollar}, respectively. We observed no substitution reactions in thin films of BPS and BOS. In this case, the reactions may be obstructed by steric congestion of the surface-immobilized reaction centers.; Thin layers of polyethylenimine (PEI), crosslinked with a diepoxide resin, were immobilized on surfaces modified with GPS. Temperature and pH-dependent cyclovoltammetry indicates good durability of these surfaces in the range from 25{dollar}spcirc{dollar} to 100{dollar}spcirc{dollar}C and pH 3 to 9. Polyelectrolytes, derived from 1.4-diazabicyclo (2.2.2) octane and 1.4-dibromobutane, were attached on surfaces modified with APS or PEI. |
