X-ray photoelectron spectroscopy of silica surfaces treated with polyfunctional silanes

Abstract

Results of X-ray photoelectron spectroscopic studies on the surface of silicon wafers sllanlzed with dlchlorodlmethylsllane, methyltrichlorosilane, ((glycklyloxy)propyl)trlmethoxysllane, (amlnopropyl)trlethoxysllane, tort -butyldlmethylchlorosllane, and the 12-dlchloromonomethylsllyl and 12-monochlorodlmethylsllyl ethers of methyl 12-hydroxydodecanoate are reported. The upward shift In the SI (2p) binding energies (by 0.5 eV) of surface silicons treated with silylatlng agents In the presence of Et3N was attributed to hydroxyl functionalities on these atoms. The extent of surface coverage was computed from the surface Sksubstrate SI ratios. Large differences In reactivities of the silylating agents were observed in the presence or absence of the base catalyst.

Fast atom bombardment mass spectrometry of some alkoxv‐ and chloro‐silanes

“…In the case of 1, the ions at m/z 323 and 321 seem to arise from loss of ethanol from the MH+ and [M -H]+ ions corresponding to the siloxane of relative molecular mass 368.Since the m/z 277 ion is also present in the FAB spectrum of 1 as a neat liquid, it appears that the amino moiety of 1 effects an autocatalytic hydrolytic cleavage of an ethoxy group. Such a phenomenon has already been reported during the silanization of hydroxylic surfaces with the silane l 23. …”

Quantitative Analysis and Efficient Surface Modification of Silica Nanoparticles

“…The aminofunctional groups are known to enhance the dispersibility and miscibility of silica fibers [12], and to be used as a linkage unit to attach other functional molecules [13]. The surface modification of silica has been investigated in bulk surfaces and micron size silica beads by many characterization techniques [14][15][16][17][18][19]. A reaction mechanism was suggested as through the interaction between the amino group of APTES and surface Si-OH group in anhydrous condition [14,[20][21][22] or through the self catalytic effect of the amino group of APTES in polar alcoholic condition [23].…”

“…The surface modification of silica has been investigated in bulk surfaces and micron size silica beads by many characterization techniques [14][15][16][17][18][19]. A reaction mechanism was suggested as through the interaction between the amino group of APTES and surface Si-OH group in anhydrous condition [14,[20][21][22] or through the self catalytic effect of the amino group of APTES in polar alcoholic condition [23]. Interestingly, it was known that aminofunctional trialkoxysilanes such as APTMS and APTES are readily soluble in water to give solutions of unlimited stability at their natural pH in which normal organotrialkoxysilanes cause rapid condensation of Si-OH groups to form insoluble gels, and the internal hydrogen bonding was suggested to explain their lack of reactivity [12].…”

Spectroscopic evaluation of surface functionalization efficiency in the preparation of mercaptopropyltrimethoxysilane self-assembled monolayers on glass

“…The surface silanols react with the Si-OH groups of the hydrolyzed trialkoxysilane (stage a) [8], with the formation of Si (surface) -O-Si bridges (stage b) [9]. The remaining Si-OH groups of the hydrolyzed trialkoxysilanes are positioned in such a way that Si-O-Si bridges can be formed with an analogous vicinal fragment (stage c) [9].…”

“…The remaining Si-OH groups of the hydrolyzed trialkoxysilanes are positioned in such a way that Si-O-Si bridges can be formed with an analogous vicinal fragment (stage c) [9]. The synthesis involves the formation of authentic covalent bonds and some authors pointed out that this is not a proper self-assembling process, because the steps are not * Corresponding author.…”