Preparation and surface modification mechanism of silica aerogels via ambient pressure drying

2011 ◽  
Vol 129 (1-2) ◽  
pp. 308-314 ◽  
Author(s):  
Guoyou Wu ◽  
Yuxi Yu ◽  
Xuan Cheng ◽  
Ying Zhang
Keyword(s):  
Surface Modification ◽  
Ambient Pressure ◽  
Silica Aerogels ◽  
Ambient Pressure Drying

A Novel Route for Preparation of Transparent and Superhydrophobic Silica Aerogels

2009 ◽  
Vol 1234 ◽  
Author(s):  
Guo-you Wu ◽  
Xuan Cheng ◽  
Yu-xi Yu ◽  
Ying Zhang
Keyword(s):  
Surface Modification ◽  
Ambient Pressure ◽  
Sol Gel ◽  
Three Dimensional ◽  
Silica Aerogels ◽  
Ambient Pressure Drying ◽  
Nanoporous Structure ◽  
Surface Areas ◽  
Superhydrophobic Silica ◽  
Dta Curve

AbstractSilica aerogels were synthesized via sol-gel processing followed by a two-step surface modification and ambient pressure drying, using methyltrimethoxysilane (MTMS) and trimethylchlorosilane (TMCS)/ethanol/n-hexane as surface modification agents. The transparent silica aerogels possessed the porosities, densities and specific surface areas in the range of 87.7–92.3%, 0.27–0.17 g·cm-3 and 852–1005 m2·g-1, respectively. The SEM and HRTEM analysis revealed the three-dimensional nanoporous structure of the silica aerogels. The presence of –CH3 functional groups on the surface of silica particles as indicated by the FTIR spectra was further confirmed by two visible exothermic peaks at 310 and 450–500 °C from the DTA curve. In addition, the silica aerogels were superhydrophobic with the contact angle as high as 160°.

scholarly journals Silica Aerogel Monoliths Derived from Silica Hydrosol with Various Surfactants

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3192 ◽  
Author(s):  
Dong Chen ◽  
Xiaodong Wang ◽  
Wenhui Ding ◽  
Wenbing Zou ◽  
Qiong Zhu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Silica Aerogel ◽  
Low Cost ◽  
Ambient Pressure ◽  
Silica Aerogels ◽  
Ambient Pressure Drying ◽  
Low Thermal Conductivity ◽  
Silica Hydrosol ◽  
High Production Cost

Owing to their ultra-low thermal conductivity, silica aerogels are promising thermal insulators; however, their extensive application is limited by their high production cost. Thus, scientists have started to explore low-cost and easy preparation processes of silica aerogels. In this work, a low-cost method was proposed to prepare silica aerogels with industrial silica hydrosol and a subsequent ambient pressure drying (APD) process. Various surfactants (cationic, amphoteric, or anionic) were added to avoid solvent exchange and surface modification during the APD process. The effects of various surfactants on the microstructure, thermal conductivity, and thermal stability of the silica aerogels were studied. The results showed that the silica aerogels prepared with a cationic or anionic surfactant have better thermal stability than that prepared with an amphoteric surfactant. After being heated at 600 °C, the silica aerogel prepared with a cationic surfactant showed the highest specific surface area of 131 m2∙g−1 and the lowest thermal conductivity of 0.038 W∙m−1∙K−1. The obtained low-cost silica aerogel with low thermal conductivity could be widely applied as a thermal insulator for building and industrial energy-saving applications.

scholarly journals Eco-friendly approach for preparation of water-based superhydrophobic silica aerogels via ambient pressure drying

2021 ◽  
Vol 8 (1) ◽  
pp. 015021
Author(s):  
Xiaoling Yuan ◽  
Lihui Xu ◽  
Hong Pan ◽  
Yong Shen ◽  
Liming Wang ◽  
...  
Keyword(s):  
Ambient Pressure ◽  
Silica Aerogels ◽  
Ambient Pressure Drying ◽  
Water Based ◽  
Superhydrophobic Silica
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