نتایج جستجو برای: aerogels

تعداد نتایج: 1389  

2013
Julio C. Arboleda Mark Hughes Lucian A. Lucia Janne Laine Kalle Ekman Orlando J. Rojas

Organic aerogels based on two important and widely abundant renewable resources, soy proteins (SP) and nanofibrillar cellulose (NFC) are developed from precursor aqueous dispersions and a facile method conducive of channeland defect-free systems after cooling and freeze-drying cycles that yielded apparent densities on the order of 0.1 g/cm. NFC loading drives the internal morphology of the comp...

Journal: :Science and technology of advanced materials 2008
Uzma K H Bangi A Venkateswara Rao A Parvathy Rao

An in-depth investigation into the synthesis of hydrophobic silica aerogels prepared by the surface derivatization of wet gels followed by subsequent drying at ambient pressure is reported. The following sol-gel parameters were examined for their effect on the physical properties of the derived aerogels: number of gel washings with water, percentage of hexane or methanol in silylating mixture, ...

Journal: :Advanced materials 2017
Bin Cai Arezoo Dianat René Hübner Wei Liu Dan Wen Albrecht Benad Luisa Sonntag Thomas Gemming Gianaurelio Cuniberti Alexander Eychmüller

A new class of multimetallic hierarchical aerogels composed entirely of interconnected Ni-Pdx Pty nano-building-blocks with in situ engineered morphologies and compositions is demonstrated. The underlying mechanism of the galvanic shape-engineering is elucidated in terms of nanowelding of intermediate nanoparticles. The hierarchical aerogels integrate two levels of porous structures, leading to...

Journal: :Chemical communications 2014
Felix Rechberger Gabriele Ilari Markus Niederberger

We present the assembly of preformed antimony doped tin oxide nanobuilding blocks into centimeter sized aerogels with surface areas exceeding 340 m(2) g(-1). After calcination, the resistivity of the aerogels was decreased by 4 orders of magnitude to a few kΩ cm, with the primary conducting structures measuring only a few nanometers.

2012
M. Robitzer A. Tourrette R. Horga R. Valentin M. Boissière F. Di Renzo F. Quignard Charles Gerhardt

Supercritically dried aerogels of several polysaccharides (chitin, chitosan, alginate, alginic acid, kcarrageenan, andagar) havebeencharacterisedbyphysisorptionofN2. Surface areas ashighas570m g have been measured. The nature of the functional groups of the polysaccharide significantly influences the adsorption of N2 on the surface of the aerogel. The net enthalpy of adsorption increases with t...

2017
Kyle J Lynch Omar Skalli Firouzeh Sabri

Fundamental understanding and characterization of neural response to substrate topography is essential in the development of next generation biomaterials for nerve repair. Aerogels are a new class of materials with great potential as a biomaterial. In this work, we examine the extension of neurites by PC12 cells plated on matrigel-coated and collagen-coated mesoporous aerogel surfaces. We have ...

2004
D. R. Vollet D. A. Donatti A. Ibañez Ruiz

A comparative study using small-angle x-ray scattering ~SAXS! and nitrogen adsorption has been carried out in the structural characterization of silica xerogels and aerogels, obtained from tetraethoxysilane sonohydrolysis. The specific surface and the mean pore size as measured by both the techniques were found to be in notable agreement in all cases for aerogels and xerogels. According to the ...

Journal: :Optics express 2009
Pradeep Bhupathi Jungseek Hwang Rodica M Martin Jackson Blankstein Lukas Jaworski Norbert Mulders David B Tanner Yoonseok Lee

Optical transmission measurements were made on 98% porosity silica aerogel samples under various degrees of uniaxial strain. Uniaxially compressed aerogels exhibit large birefringence, proportional to the amount of compression, up to the 15% strain studied. The birefringence is mostly reversible and reproducible through multiple compression-decompression cycles. Our study demonstrates that unia...

Journal: :Chemical reviews 2002
Alain C Pierre Gérard M Pajonk

In the present review, aerogels designate dried gels with a very high relative pore volume. These are versatile materials that are synthesized in a first step by low-temperature traditional sol-gel chemistry. However, while in the final step most wet gels are often dried by evaporation to produce so-called xerogels, aerogels are dried by other techniques, essentially supercritical drying. As a ...

Aerogels are a special class of porous material, which have excellent physicochemical properties such as low density, high porosity, high surface area and adjustable surface chemistry. Aerogels were first prepared several decades ago, but never truly commercialized due to their high cost. Technological advancements in the production and quality of different types of aerogel cut costs down and m...

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