Aqueous silane-surfactant co-dispersions for deposition of hydrophobic coatings onto pre-oxidized polysilicon

Abstract

The application of hydrophobic coatings onto pre-oxidized polysilicon substrates is an effective method to prevent or reduce "release" as well as "in-use" stiction in microelectromechanical systems (MEMS). A chemical system consisting of a commercially available water dispersible silane (Siliclad ® ) has previously been shown to be useful in rendering polysilicon surfaces hydrophobic. In this paper, the improvement of the stability of such a chemical system is described. The objectives of the work reported in this paper are: (1) to characterize the stability of the organosilane in aqueous solutions under conditions suitable for the formation of hydrophobic coatings and (2) to investigate the influence of cationic surfactants on gelation rate of silane dispersions, on the adsorption of organosilane molecules onto pre-oxidized polysilicon and on the hydrophobic character of the coatings. Additionally, the effect of chain length and concentration for a series of alkyltrimethylammonium (C 12 ,C 14 ,C 16 ) bromide surfactants on dispersion stability has been investigated.

Immobilized silver nanoparticles enhance contact killing and show highest efficacy: elucidation of the mechanism of bactericidal action of silver

“…35 The water content during the immobilization protocol was precisely optimized since an absence of water leads to the formation of incomplete silane layers, while an excess of it gives a non-uniform silane lm due to pre-deposition oligomerization. 31 A pH range of 3.2 to 3.7 was maintained during the silanization step so as to orient the amine groups away from the glass surface, 36 and to facilitate interaction between the AgNPs and silane moieties. 31 The surface underwent a thorough water rinse and ultrasonication before further use.…”

Kinetics of fluoride-catalysed synthesis of organosilica colloids in aqueous solutions of amphiphiles

“…900, 1040, 1120, and 1260 cm À1 ) have been assigned for indicating silane poly-condensation and the formation of Si-O-Si bonds. [42][43][44][45][46] Furthermore, to demonstrate the change of hydrophilic interactions within the reaction system over time, the absorbance spectra that cover water's stretching and bending vibrations are shown in Fig. 6B and S3, † respectively.…”

Superhydrophobic coating on modified 9Cr – 1Mo ferritic steel using perfluoro octyl triethoxy silane

“…The band at 980-890 cm 21 was assigned to the Si-OH band. 42 The peaks observed *700-800 cm 21 were due to the vibrations of Si-O groups in the PFOTES solution. Moreover, peaks *1145 cm 21 , 1242 cm 21 and 1147 cm 21 , 1244 cm 21 were attributed to the vibrations of CF 2 and CF 3 groups of specimens II and III respectively.…”