Highly transparent silica aerogel thick films with hierarchical porosity from water glass via ambient pressure drying

He, Peng; Gao, Xiangdong; Li, Xiaomin; Jiang, Zhengwu; Yang, Zhenghong; Wang, Cailu; Gu, Zhengying

doi:10.1016/j.matchemphys.2014.04.007

Cited by 20 publications

(12 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The rest of wet beads were modified by Trimethylchlorosilane 50 (TMCS) via simultaneous solvent exchange/surface modification which has been reported previously 8 . The sample named as Sil-M.…”

Section: Preparation Of Hydrophilic Silica Aerogel Beads Via Simultanmentioning

confidence: 99%

“…Due to this silica aerogel beads are the small spheroid, solvent exchange process is much faster and 35 the beads are regularity and more convenient for application; this can considerably improve the product quality and reduce the production time and cost. Silica aerogel beads have recently been synthesized at ambient pressure, many researchers had made a great contribution [8][9][10][11] . Although these methods are much easier, 40 the key step to obtain the silica beads of synthesis path is tedious and unmanageable, and the solution is complex and difficult to recycle.…”

Section: Introductionmentioning

confidence: 99%

“…Different from the previous reports 8 , a kind of high viscosity oil phase (dimethyl silicon oil) was used to replace the complex solution phases aim to make the reaction easy to control and keep the wet gel with highly degree of sphericity. In order to improve skeleton strength of the gel, wet 55 silica beads were aging by immersing in large volume of tetraethoxysilane (TEOS)-ethanol-water solution to reduce shrinkage during drying.…”

Section: Introductionmentioning

confidence: 99%

“…Silica aerogel beads have recently been synthesized at ambient pressure, many researchers had made a great contribution. [8][9][10][11] Although these methods are much easier, the key step to obtain the silica beads is tedious and unmanageable, and the solution is complex and difficult to recycle. In addition, both the hydrophobic and hydrophilic aerogel beads have obvious crack because of surface modication and heat-treated.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Characterization and comparison of uniform hydrophilic/hydrophobic transparent silica aerogel beads: skeleton strength and surface modification

et al. 2015

View full text Add to dashboard Cite

Hydrophilic mesoporous sodium silicate-based silica aerogel beads were produced by skeleton improvement of wet silica beads by ambient pressure drying. This preparation method is suitable for economic and large-scale industrial production of silica aerogel beads. AbstractSilica aerogel is a kind of good adsorbents due to the large surface areas and chemical stability. However, its inherent poor mechanical properties and hydrophobicity limited applications in water treatment. To improve the adsorption performance of silica aerogel, uniform transparent hydrophilic mesoporous silica 10 aerogel beads with highly degree of sphericity were synthesized through a facile aging immersion and ambient pressure drying route. The designed hydrophilic silica aerogel beads possessed the mesopores, mean diameter of approximately with the average pore size of 12.51 nm, the specific surface area of 582.52 m 2 g -1 , and the pore volume of 1.46 cm 3 g -1 . For comparison, hydrophilic silica aerogel beads without skeleton improvement and hydrophobic silica aerogel beads were also obtained, respectively. The 15 synthesized novel hydrophilic silica aerogel beads displayed a significantly improved adsorption performance with a favorable dye absorption capacity, superior to that of previously systhesised silicabased aerogel beads materials. This study demonstrates a facile and low-cost route toward transparent silica aerogel beads with macroscopic beads structures, which can be used as adsorbents, catalytic supports or the template to synthesize novel functional materials requiring high transmittance, high 20 surface area and effective mass transport. 65 which showed excellent physicochemical properties as well as remarkable adsorption performance effect.

show abstract

Section: Preparation Of Hydrophilic Silica Aerogel Beads Via Simultanmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Characterization and comparison of uniform hydrophilic/hydrophobic transparent silica aerogel beads: skeleton strength and surface modification

et al. 2015

View full text Add to dashboard Cite

show abstract

“…However, uniform crack‐free silica aerogel films of more than a few microns have not been reported yet, to the best of our knowledge. He et al [7] deposited highly transparent silica aerogel films of <3.6 µm on fluorine doped tin oxide glass via a doctor‐blade method, for applications in intermetal dielectrics. However, they stated that the films were uniform only up to the thickness of 2.9 µm and that they could not prepare good aerogel films by spin‐ or dip‐coating due to the high surface tension of the aqueous water glass precursor.…”

Section: Introductionmentioning

confidence: 99%

Silica aerogel thick film, an alternative to micromachined air gap for thermal insulation

Seyedjalali

Madani

2015

Electron. lett.

View full text Add to dashboard Cite

A uniform, smooth and crack-free multilayer silica aerogel film as thick as 5 µm is successfully coated on top of a silicon wafer. The multilayer spin-coated aerogel film was made possible by using the present authors' recently developed novel state-of-the-art aerogel processing technique. The utilisation of the thick aerogel film for the thermal insulation of a microhotplate (µHP) is studied. The super heat insulator aerogel can replace the micromachined air cavity conventionally created under µHPs for the fabrication of metal oxide gas sensors. The thermal insulation capability of the unique aerogel film was investigated by measuring the temperature of the nichrome heaters built on the aerogel coated silicon wafers at different applied powers. The temperature coefficient of the resistivity of the heaters was measured by monitoring the change in the resistance of the heaters at different temperatures. Simulations were also performed using COMSOL multiphysics software for verification of the experimental results, showing good agreement.Introduction: General metal oxide (MOX) gas sensors utilise a thin membrane suspended in the air cavity created by micromachining the silicon to thermally insulate the heated components from the substrate [1-3]. A drawback of this approach is the high fragility and low mechanical stability of the thin (a few microns or less) membranes during processing and operation [4]. In addition, the lithographic processing of MOX sensing on top of the suspended layers becomes impossible due to the fact that the front side micromachined structures contain etch troughs and therefore the surface is not flat [5], hence the micromachining must be done as a post-process after the sensor electrodes are processed which lowers the yield drastically.We have previously reported [6] the thermal insulating capability of a monolayer thin film silica aerogel of <1 µm thickness, processed on a silicon wafer through supercritical drying, for developing ultra-dense and ultra-low-power microhotplates, to replace the air cavity conventionally created by the micromachining of wafers. However, uniform crack-free silica aerogel films of more than a few microns have not been reported yet, to the best of our knowledge. He et al.[7] deposited highly transparent silica aerogel films of <3.6 µm on fluorine doped tin oxide glass via a doctor-blade method, for applications in intermetal dielectrics. However, they stated that the films were uniform only up to the thickness of 2.9 µm and that they could not prepare good aerogel films by spin-or dip-coating due to the high surface tension of the aqueous water glass precursor. Bauer et al.[8] developed silica aerogel films of only 0.25-1.28 µm thickness via several laborious solvent exchange steps, and measured the thermal conductivity as 0.024 W/m/K to ensure the insulation capability of aerogel films. Wang and Wu [9] evaluated the electrical sensing properties of silica aerogel thin films to humidity, fabricated on a alumina substrate by dip-coating silica colloid followed b...

show abstract

Transparent Silica Aerogels: Optical and Chemical Design, Controlled Synthesis, and Emerging Applications

Xie,

Wang,

et al. 2024

Chemistry An Asian Journal

View full text Add to dashboard Cite

Transparent silica aerogel, serving as one typical porous and transparent material, possesses various unique features (e.g., large amounts of pores and interfaces, super‐lightweight, super thermal insulation, low refractive index similar to gas), and it has attracted great attention in the fields of science, technology, engineering, art, and others. Transparency is one important evaluation index of transparent silica aerogel, and it was influenced by various factors such as raw materials, sol‐gel reactions, phase separation, and drying methods. The structure design and fabrication of transparent silica aerogel is one huge and fine engineering. In this review, the optical/chemical guidance and design for the preparation of transparent silica aerogels are discussed, and typical applications, such as Cherenkov detectors, solar energy collection, lighting systems, and transparent fabric, also were discussed. Finally, a future outlook on the opportunities and challenges of transparent silica aerogels was proposed.

show abstract

Highly transparent silica aerogel thick films with hierarchical porosity from water glass via ambient pressure drying

Cited by 20 publications

References 34 publications

Characterization and comparison of uniform hydrophilic/hydrophobic transparent silica aerogel beads: skeleton strength and surface modification

Characterization and comparison of uniform hydrophilic/hydrophobic transparent silica aerogel beads: skeleton strength and surface modification

Silica aerogel thick film, an alternative to micromachined air gap for thermal insulation

Transparent Silica Aerogels: Optical and Chemical Design, Controlled Synthesis, and Emerging Applications

Contact Info

Product

Resources

About