Inorganic Aerogel Granules Dried at Atmospheric-Pressure

Silica aerogels using sodium silicates was synthesized by atmospheric-pressure drying. Granulation of silica aerogels was carried out in sequence of hydrogel formation, aging, surface modification, and drying. Rapidly prepared aerogels showed good properties in case aging and surface modification was done within 1 day. Drying is critical to aerogel granulation and the BET area of aerogel dried for a short duration had decreasing with time. It is suggested that sodium silicate-based aerogels granulation could be prepared within less than 5 days, half of initial processing. Aerogel granules had the average diameter of 1 mm and nearly spherical shape. It has very low thermal conductivity of 0.010 W/m⋅K, very light-weight and nanoporous structure with a porosity of upto 95%.

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A Novel Route for Preparation of Transparent and Superhydrophobic Silica Aerogels

MRS Proceedings ◽

10.1557/proc-1234-qq06-12 ◽

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°.

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Study of the influence of various solvents on the properties of hydrophobic silica xerogels

Transaction Kola Science Cetnre ◽

10.37614/2307-5252.2021.2.5.026 ◽

2021 ◽

Vol 12 (2-2021) ◽

pp. 129-130

Author(s):

A. A. Kolmakova ◽

◽

A. E. Baranchikov ◽

Keyword(s):

Atmospheric Pressure ◽

Three Dimensional ◽

Silica Aerogels ◽

Nanoporous Materials ◽

Optimal Combination ◽

Nanoporous Structure ◽

Low Density ◽

Silica Xerogels ◽

Hydrophobic Silica ◽

Alcohol Solvents

Silica aerogels are low-density inorganic aerogels with a three-dimensional nanoporous structure. Due to the inherent properties of nanoporous materials, the possibility of using silica airgel is of great interest in various fields. To simplify the process and reduce costs, the use of atmospheric pressure drying (APD) is promising, the resulting materials are called xerogels. Silica xerogels based on methyltrimethoxysilane were synthesized using various alcohol solvents. The optimal combination of properties is possessed by a sample obtained using methanol as a solvent. The wetting angle of all xerogels was 158°, which characterizes the resulting material as superhydrophobic.

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Structural characteristics and thermal conductivity of ambient pressure dried silica aerogels with one-step solvent exchange/surface modification

Materials Chemistry and Physics ◽

10.1016/j.matchemphys.2008.07.124 ◽

2009 ◽

Vol 113 (1) ◽

pp. 485-490 ◽

Cited By ~ 50

Author(s):

Li-Jiu Wang ◽

Shan-Yu Zhao ◽

Mei Yang

Keyword(s):

Thermal Conductivity ◽

Surface Modification ◽

Structural Characteristics ◽

Ambient Pressure ◽

Silica Aerogels ◽

Solvent Exchange ◽

One Step ◽

Exchange Surface

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Direct Bonding between Silicone and Glass by Atmospheric-Pressure Surface Modification

IEEJ Transactions on Sensors and Micromachines ◽

10.1541/ieejsmas.131.159 ◽

2011 ◽

Vol 131 (4) ◽

pp. 159-164 ◽

Cited By ~ 2

Author(s):

Wataru Okada ◽

Takatoki Yamamoto

Keyword(s):

Surface Modification ◽

Atmospheric Pressure ◽

Pressure Surface

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Surface modification of PMMA polymer and its composites with PC61BM fullerene derivative using an atmospheric pressure microwave argon plasma sheet

Scientific Reports ◽

10.1038/s41598-021-88553-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Andrzej Sikora ◽

Dariusz Czylkowski ◽

Bartosz Hrycak ◽

Magdalena Moczała-Dusanowska ◽

Marcin Łapiński ◽

...

Keyword(s):

Contact Angle ◽

Surface Modification ◽

Chemical Composition ◽

Water Contact Angle ◽

Plasma Sheet ◽

Atmospheric Pressure ◽

Argon Plasma ◽

Fullerene Derivative ◽

Water Contact ◽

Pmma Polymer

AbstractThis paper presents the results of experimental investigations of the plasma surface modification of a poly(methyl methacrylate) (PMMA) polymer and PMMA composites with a [6,6]-phenyl-C61-butyric acid methyl ester fullerene derivative (PC61BM). An atmospheric pressure microwave (2.45 GHz) argon plasma sheet was used. The experimental parameters were: an argon (Ar) flow rate (up to 20 NL/min), microwave power (up to 530 W), number of plasma scans (up to 3) and, the kind of treated material. In order to assess the plasma effect, the possible changes in the wettability, roughness, chemical composition, and mechanical properties of the plasma-treated samples’ surfaces were evaluated by water contact angle goniometry (WCA), atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The best result concerning the water contact angle reduction was from 83° to 29.7° for the PMMA material. The ageing studies of the PMMA plasma-modified surface showed long term (100 h) improved wettability. As a result of plasma treating, changes in the samples surface roughness parameters were observed, however their dependence on the number of plasma scans is irregular. The ATR-FTIR spectra of the PMMA plasma-treated surfaces showed only slight changes in comparison with the spectra of an untreated sample. The more significant differences were demonstrated by XPS measurements indicating the surface chemical composition changes after plasma treatment and revealing the oxygen to carbon ratio increase from 0.1 to 0.4.

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