Sodium hydroxide catalysed silica sol-gel synthesis: Physicochemical properties of silica nanoparticles and their post-grafting using C8 and C18 alkyl-organosilanes

被引：12

作者：

Gosiamemang, Tsaone ^{[1
]}

Heng, Jerry Y. Y. ^{[1
]}

机构：

[1] Imperial Coll London, Dept Chem Engn, London SW7 2AZ, England

来源：

POWDER TECHNOLOGY | 2023年 / 417卷

关键词：

Silica; Stober synthesis; Superhydrophobic; Silanol groups; Silica hydroxylation; PARTICLES; FUNCTIONALIZATION; RESISTANCE; SURFACES; FABRICS; SPHERES; GROWTH; COTTON;

D O I：

10.1016/j.powtec.2023.118237

中图分类号：

TQ [化学工业];

学科分类号：

0817 ;

摘要：

Sodium hydroxide (NaOH) has been shown to result in fast nucleation of highly monodispersed silica nano-particles (SNPs). However, limited work has been reported on the physicochemical properties of the resulting SNPs and their surface modification. Herein, we demonstrate that NaOH results in poor hydrolysis of silica precursor, SNPs with adsorbed sodium ions and thermally unstable siloxane cross-linkage. The sodium ions are removed by refluxing SNPs in a 4 vol% hydrochloric acid solution. This step was also found to significantly improve the thermal stability of SNPs. The surface chemistry of the SNPs was easily modified with 0.74 mmol/g of octyltrimethoxysilane and 0.42 mmol/g of octadecyltrimethoxysilane. Functionalised SNPs exhibited super-hydrophobicity (water contact angle >= 150 degrees) and displayed a decrease between 2.46% to 3.03% in moisture sorption at 95% relative humidity. The results reveal that the acid treatment will be crucial in the design of hydroxylated and thermally stable SNPs from NaOH-catalysed synthesis.

引用

页数：8