Effect of the type of fluorofunctional organosilicon compounds and the method of their application onto the surface on its hydrophobic properties

Abstract

Fluorofunctional silanes, polysiloxanes and silsesquioxanes were used for the modification of glass surfaces and their influence on hydrophobic properties were determined. To increase hydrophobicity of the surface, the modification was performed in two stages: (i) by a pretreatment using a silica sol (a rise in the surface roughness), and (ii) modification with the above silicon compounds. The hydrophobicity was determined by measuring the contact angle by drop profile tensiometry. The fluorocarbofunctional organosilicon derivatives examined were found to be good precursors for the synthesis of highly hydrophobic materials and coatings. In some cases the contact angles measured after surface modification exceeded 150 , i.e. they fell in the range characteristic of superhydrophobic surfaces.

Preparation of highly hydrophobic cotton fabrics by modification with bifunctional silsesquioxanes in the sol-gel process

“…In the case of the derivatives 1 and 3, the hydrophobic properties were strong which indicates that the derivatives that bound to the substrates via triethoxysilyl groups are better hydrophobizing agents compared to epoxy groups (2 and 4). However, somewhat surprising is a relatively low value of water contact angle on surfaces modified by the derivatives containing seven fluoroalkyl groups because usually a higher fluorine content results in hydrophobicity increase as it was observed in our earlier study on the modification of glass surfaces [46]. Additionally, our research has shown that very good hydrophobizing effects can be obtained using glycidoxypropyl group-containing derivatives.…”

“…The latter groups can react with surface hydroxyl groups and, moreover, due to their longer chain (compared to trialkoxysilyl group present in the derivatives 1-3) they can cause a greater surface diversification [45,46]. The most likely reason for this disparity is the different nature of surface hydroxyl groups.…”

“…Concurrently, an increase in the surface roughness has been observed, however, on a nanoscale, which results from the size of silsesquioxane molecules. In our earlier studies on the modification of glass surfaces we have noticed that in some cases the modification with silsesquioxanes resulted even in a surface smoothing (a reduction in roughness) caused by their nanometric dimensions and filling cracks and scratches present on the surface of unmodified glass [46].…”

“…In this way, silsesquioxanes were synthesized which contain also trimethoxysilyl or glycidyl groups besides fluoroalkyl groups. The reactivity of trimethoxysilyl and glycidyl groups causes that they can form stable bonds with the substrate as a result of reactions with hydroxyl groups present on the surface [45,46].…”

Facile preparation of superhydrophobic and oleophobic surfaces via the combination of Cu(0)‐mediated reversible‐deactivation radical polymerization and click chemistry

“…The application of nanosilica organic/inorganic hybrid materials has been demonstrated in the preparation of hydrophobic and superhydrophobic surfaces by many research groups. 49,53,[59][60][61][62][63][64] However, in many cases a long fluorinated chain, usually on the silane coupling agent, was used to provide superhydrophobicity. 49,[60][61][62][63][64] In some cases, the nanosilica was used in combination with the layer-by-layer…”