Thermally Induced Silane Dehydrocoupling on Silicon Nanostructures

Abstract

Organic trihydridosilanes can be grafted to hydrogen-terminated porous Si nanostructures with no catalyst. The reaction proceeds efficiently at 80 8 8C, and it shows little sensitivity to air or water impurities.T he modified surfaces are stable to corrosive aqueous solutions and common organic solvents.O ctadecylsilane H 3 Si(CH 2 ) 17 CH 3 ,a nd functional silanes H 3 Si(CH 2 ) 11 Br,H 3 Si(CH 2 ) 9 CH = CH 2 ,and H 3 Si(CH 2 ) 2 -(CF 2 ) 5 CF 3 are readily grafted. When performed on amesoporous Si wafer,the perfluoro reagent yields asuperhydrophobic surface (contact angle 1518 8). The bromo-derivative is converted to azide,a mine,o ra lkyne functional surfaces via standardt ransformations,a nd the utility of the method is demonstrated by loading of the antibiotic ciprofloxaxin (35 % by mass). When intrinsically photoluminescent porous Si films or nanoparticles are used, photoluminescence is retained in the grafted products,i ndicating that the chemistry does not introduce substantial nonradiative surface traps. Scheme 1. Proposed dehydrogenativecoupling reactions between trihydridosilanes and hydrogenated silicon in the presence of air.

Systematic Degradation Rate Analysis of Surface-Functionalized Porous Silicon Nanoparticles

“…The attenuated total reflectance Fourier-transform infrared (ATR-FTIR, Thermo Fisher Scientific, Waltham, MA, USA) spectrum of the pSiNPs samples was monitored ( Figure 4 ). The infrared spectrum of the pSiNPs-OH displayed bands associated with the Si–O–H functionality; broad band for υ(O–H) at 3550–3200 cm −1 , υ(Si–O) at 1065 nm −1 (black trace) [ 3 , 30 , 31 ]. The other pSiNPs samples showed strong bands at 2950–2850 cm −1 , 1480–1350 cm −1 , and 1360–1080 cm −1 associated with υ(C–H), δ(C–H), and υ(amide bond), respectively, which derived from the PEG linker.…”

“…The surface modification of pSiNPs is imperative in improving their properties and usage [ 3 , 28 , 29 , 30 ]. Freshly prepared pSiNPs have silicon hydroxide (Si–OH) functionality, primarily with minor silicon hydride (Si–H) and silicon oxide bridge (Si–O–Si).…”

A Mini Review: Recent Advances in Surface Modification of Porous Silicon

“…However, this dehydrogenative coupling method requires transition metal catalysts in order to effect the transformation, and the highly reactive catalysts can lead to an oxidative side reaction. Very recently, Kim and co-workers reported the non-catalytic dehydrocoupling reaction can proceed under mild thermal conditions on the pSi surface (Method B, Figure 5b) [58,59]. The first investigation was successfully carried out with the pSi film and an octadecysilane, H 3 Si(CH 2 ) 17 CH 3 (abbreviated as H 3 Si-C 18 ).…”

“…( d ) Water contact angle image and illustration of the surface after reaction. Reproduced with permission from [58]. Copyright 2016 Wiley-VCH.…”

Thermally Induced Silane Dehydrocoupling: Hydrophobic and Oleophilic Filter Paper Preparation for Water Separation and Removal from Organic Solvents

“…In this study, for the first time, we introduced a simple method for the preparation of hydrophobic and oleophilic filter paper (named OCFP) based on thermally induced silane dehydrocoupling ( Figure 1 b). OCFP was prepared via a thermally induced silane dehydrocoupling reaction between cellulose-based filter paper (CFP) and octadecylsilane paper under mild reaction conditions without adding any catalyst [ 42 ]. We confirmed its high separation efficiency of the residual water from the organic solvents without decomposition of the membrane structure or tensile strength, tensile modulus, or elongation.…”