Preparation and self-assembly of carboxylic acid-functionalized silica

A simple method for the fabrication of silica nanoparticle film based on the covalent-bonding interaction between carboxylic acid-functionalized silica nanoparticles (SiO2-COOH) and amino-terminated silicon wafer was developed. Prior to assembly, silica nanoparticles with an average diameter 80 nm were prepared using the Stober method, amino-functionalized silica nanoparticles (SiO2-NH2) were prepared by a silanization with 3-aminopropyltriethoxysi lane (APTES), while carboxylic acid-functionalized silica nanoparticles NO2-COOH) were prepared by a ring opening linker elongation reaction of the amine functions with succinic anhydride, at the same time, amino-terminated silicon wafer (Si-NH2) was obtained by self-assembling 3-aminopropyltriethoxysi lane, then one layer relative close-packed carboxylic acid-functionalized silica nanoparticles NO2-COOH) was arranged on silicon wafer through amidation reaction under DCC coupling agent. (c) 2007 Elsevier Inc. All rights reserved.