Instituto de Ciencia y Tecnologia de Polimeros (CSIC), Juan de la Cierva, 3, 28006 Madrid, Spain.
Langmuir. 2010 Apr 20;26(8):5499-506. doi: 10.1021/la903743n.
The scope of this work is the comparative analysis in terms of grafting rate, structure of the grafted layer, and wetting behavior of three series of silica nanoparticles modified with alkyltrimethoxysilanes by using conventional heating with and without acid catalysis, and microwave irradiation. A comprehensive characterization of the grafted layer by means of Fourier transform infrared (FTIR), microanalysis, and solid state NMR techniques has shown that microwave irradiation provokes a pronounced increase in the loading rate compared to conventional heating. This microwave effect is outstanding in the case of the reactions with methyltrimethoxysilane, because of the acceleration of the condensation rate. Moreover, solid state NMR spectra ((29)Si and (13)C) strongly suggest structural differences in the grafted layer obtained by the two heating sources. The wetting behavior of the modified nanoparticles was studied, concluding that these changes in the structure of the grafted layer induced by the synthetic procedure do not determine the values of the dynamic water contact angles.
这项工作的范围是通过使用常规加热和酸催化以及微波辐射，对用烷基三甲氧基硅烷改性的三系列二氧化硅纳米粒子在接枝率、接枝层结构和润湿性方面进行比较分析。通过傅里叶变换红外（FTIR）、微分析和固态 NMR 技术对接枝层进行全面表征表明，与常规加热相比，微波辐射会显著提高接枝率。在与甲基三甲氧基硅烷的反应中，这种微波效应非常显著，因为它加速了缩合速率。此外，固态 NMR 谱（（29）Si 和（13）C）强烈表明，通过两种加热源获得的接枝层在结构上存在差异。研究了改性纳米粒子的润湿行为，得出结论，接枝层结构的这些变化不会决定动态水接触角的值。
