Preparation and Properties of Hydrophobically Modified Nano-SiO₂ with Hexadecyltrimethoxysilane

Abstract

As a common inorganic silicon material, nano-SiO 2 is extremely hydrophilic due to the presence of a large number of hydroxyl groups on its surface, which limits its application in some fields. In this research, hexadecyltrimethoxysilane (HDTMS) was used to modify nano-SiO 2 , and the results of water contact angle (WCA), Fourier transform infrared (FTIR), two-dimensional correlation spectroscopy (2D-COS), thermogravimetric (TG) analysis, and scanning electron microscopy (SEM) indicated that the hydrophobic long-chain alkyl of HDTMS was successfully grafted onto the surface of nano-SiO 2 . When the ratio of nano-SiO 2 and HDTMS was 0.25:1, the WCA of nano-SiO 2 modified with HDTMS (HDTMS-nano-SiO 2 ) reached 170.9°, which was about 5.62 times higher than that before modification, and the superhydrophobic property was obtained. The novelty of this work lies in the modified nano-SiO 2 with a WCA of over 170° and the analysis of the modification mechanism with the help of 2D-COS. This study can provide a reference for the hydrophobic modification of nano-SiO 2 and its application field expansion.

Fabrication and Characterization of Hydrophobic Cellulose Nanofibrils/Silica Nanocomposites with Hexadecyltrimethoxysilane

“…The HDTMS decomposed in a wide temperature range of ~200–500 °C, due to the relatively insufficient Si–O–Si crosslinking structure and the organic region of the hexadecyl group (–CH 2 (CH 2 ) 14 CH 3 ) [ 33 , 38 , 64 , 65 ]. Figure S2 shows the differential scanning calorimetry (DSC) curve of the CNF/silica and HDTMS-modified CNF/silica nanocomposites.…”

“…In particular, HDTMS-modified CNF/silica nanocomposites have decreased inorganic content (silica and inorganic HDTMS) compared to CNF/silica, but increased T 10 and T inf,1 , because organic HDTMS exhibits high thermal stability at a decomposition temperature from around 519 • C to 527 • C [60][61][62][63]. The HDTMS decomposed in a wide temperature range of ~200-500 °C, due to the relatively insufficient Si-O-Si crosslinking structure and the organic region of the hexadecyl group (-CH2(CH2)14CH3) [33,38,64,65]. Figure S2 shows the differential scanning calorimetry (DSC) curve of the CNF/silica and HDTMS-modified CNF/silica nanocomposites.…”

“…Thermal degradation properties (T 10 , T inf,1, T inf,2, and T max ) of the CNF, CNF/silica, h-sCNF, and h-CNF nanocomposites, and inorganic/organic component content of HDTMS for the h-CNF and h-sCNF nanocomposites. The HDTMS decomposed in a wide temperature range of ~200-500 • C, due to the relatively insufficient Si-O-Si crosslinking structure and the organic region of the hexadecyl group (-CH 2 (CH 2 ) 14 CH 3 ) [33,38,64,65]. Figure S2 shows the differential scanning calorimetry (DSC) curve of the CNF/silica and HDTMS-modified CNF/silica nanocomposites.…”

“…In addition, many well-known studies using HDTMS have been conducted to impart roughness and superhydrophobicity to the surface of silica nanoparticles. Some studies have investigated the hydrophobic surfaces of cotton or wood using a HDTMS-modified silica nanoparticle coating solution [ 33 , 34 , 35 , 36 , 37 , 38 ]. Although many previous studies have focused on the phenomenon of imparting hydrophobicity, quantitative analysis of the modification of HDTMS does not provide a sufficient explanation.…”

Selective Fabrication of Robust and Multifunctional Super Nonwetting Surfaces by Diverse Modifications of Zirconia–Ceria Nanocomposites

“…HDTMS is a silane coupling agent, usually applied in the hydrophobic functionalization of nanoparticles. 80 By surface modification of the nanocomposites with HDTMS, −CH 3 and −CH 2 groups encompass the ZrO 2 −CeO 2 composites and desirably decrease their surface energy. Then, the functionalized nanotexture is coated on the carbonate plate consisting of microscale roughness, providing a micro/nanostructure that helps achieve superhydrophobicity.…”