Comparison of Adsorption of Mercaptopropyltrimethoxysilane on Amphiphilic TiO₂ and Hydroxylated SiO₂

Abstract

Alkylsilane 3-mercaptopropyltrimethoxysilane (3MPT) monolayers with a functional end group -SH were used to immobilize Ag colloidal nanoparticles on photoinduced amphiphilic TiO(2) and hydroxylated SiO(2) surfaces. The differences in the adsorption of 3MPT and the immobilization of Ag colloids on both surfaces were studied. Under identical experimental conditions, 3MPT islands were formed on UV-exposed TiO(2) surfaces compared to continuous and flat monolayers formed on SiO(2). The significant structural differences found for monolayers of 3MPT on TiO(2) could be explained in terms of the different densities of hydroxyl groups and the microstructure of hydrophilic domains induced by UV irradiation. The surface properties were characterized using contact angle measurements and XPS. XPS showed an increase in the hydroxyl group's density and a decrease in the number of adsorbed hydrocarbon films on the TiO(2) surface as a function of the UV irradiation time. The density of the adsorbed 3MPT on TiO(2) surfaces as a function of the UV irradiation time was quantitatively related to the cosine of the water contact angles. Such a 3MPT distribution influenced the subsequent adsorption of Ag colloids and resulted in more isolated nanoparticles on the modified TiO(2) with a narrower size distribution.

Photocatalytic and Oxidative Synthetic Pathways for Highly Efficient PANI-TiO2 Nanocomposites as Organic and Inorganic Pollutant Sorbents

“…The first step involves the adsorption of aniline dimers at the oxide surface, as shown by both FTIR and XPS spectra exhibiting a loss of surface hydroxylation and a notable second component in the Ti 2p spectra. The latter effect is more marked in the presence of UV irradiation, in accordance with the literature reporting an increased omniphilicity of light-irradiated TiO2 [68]. This initial step is crucial to promote the final PANI crystallinity and porous morphology, which can be related to the controlled and oriented growth of the oligomer chains at the oxide surface, explaining the unique crystallinity degree of our samples with respect to literature composites [28,36,37,39,40].…”

SPAD aptasensor for the detection of circulating protein biomarkers

“…This increment, together with the presence of a sulfur peak, can be ascribed to the silane aliphatic chains and therefore to the actual silane coating. The chemical composition after the silane immobilization was indeed in good agreement with the literature (Lenigk et al, 2001, Zuo andTorres, 2010).…”

Gas phase silanization for silicon nanowire sensors and other lab‐on‐a‐chip systems

“…S1). The reaction protocol was derived from the corresponding literature [13][14][15], and comprised immersion in the isopropanolic silane solution for 24 h. Additionally, the substrates were also immersed for 1 h and 4 h during the present study to compare the performance for shorter reaction times. For the development of the gas phase reaction, a seminal report by Pavlovic et al [11] served as the starting point.…”