Surface Modifications Using a Water-Stable Silanetriol in Neutral Aqueous Media

Abstract

Surface modifications of glass slides employing the sterically hindered tert-butyl substituted silanetriol are described. To the best of our knowledge, this is the first time that a stable silanetriol has been directly used for this purpose. So far unprecedented, this process runs under neutral aqueous conditions and in the absence of organic solvents, which makes coating protocols accessible to acid-sensitive substrates. The layer thickness and surface topography are investigated by the Sarfus technique, by X-ray reflectivity, and by atomic force microscopy (AFM). These techniques yield values of 0.8±0.1 (XRR) and 0.6±0.2 nm (Sarfus) for layer thickness and 0.33 nm for root mean square roughness (AFM). The modified surfaces have hydrophobic and oleophilic character and contact angles (CA) between 60° (formamide, CH2I2) and 90° (water) are obtained. The thin coatings allow a structuring by UV/ozone treatment in order to get hydrophilic and hydrophobic compartments on the surfaces. For all coatings, surface free energies are calculated using different models. To determine the isoelectric points (IEP) of the modified surfaces, we performed zeta-potential measurements. Correlations between zeta potentials and hydrophilicity of the surfaces are shown.

Wettability and surface composition of partly and fully regenerated cellulose thin films from trimethylsilyl cellulose

“…As discussed in Section 3.1 and known from related cases, silanols tend to condense forming disiloxanes. Only for sterically crowded silanols, can condensation be hindered kinetically [41]. In our case hexamethyldisiloxane is readily formed and could, under the conditions given, be placed as an impurity onto the regenerated cellulose surfaces (up to 4 min RT), as long as not all the TMS-groups are cleaved off and therefore avoid the adsorption of hexamethyldisiloxane (after 6 min of regeneration).…”

A Rational Synthetic Approach to 2,5‐Diphenyl‐β‐silyl Phospholes

“…In the future we will exploit this route to investigate the effect of varying the α-substituents and the substituents at the silyl unit to tailor the optoelectronic properties of these fascinating heterocycles and to provide anchoring groups for controlled attachment to surfaces. [38] Experimental Section General: All manipulations were carried out under strict exclusion of moisture and air in an inert argon atmosphere. All solvents were dried with potassium or CaH 2 and distilled prior to use.…”

At the Edge of Stability – Preparation of Methyl‐substituted Arylsilanetriols and Investigation of their Condensation Behavior

“…[18,19] If the Si(OH) 3 moiety is however sterically protected by bulky substituents, stable and chemically robust compounds can be easily obtained with applications ranging from bioactivity to supramolecular chemistry and surface modifications. [20][21][22] Even stable silanetriols themselves may act as valuable starting materials for a controlled oligomerization as was shown recently. [17,[23][24][25][26] Since the first report of a silanetriol, i.e.…”