NanoStructured Sonogels

Author:

de la Rosa-Fox Nicolás1,Morales-Flórez Victor1,Piñero Manuel1,Esquivias Fedriani Luis Maria2

Affiliation:

1. Universidad de Cádiz, Facultad de Ciencias

2. Universidad de Sevilla, Instituto de Ciencias de los Materiales de Sevilla (CSIC).

Abstract

Acoustic cavitation effects in sol-gel liquid processing permits to obtain nanostructured materials, with size-dependent properties. The so-called “hot spots” produce very high temperatures and pressures which act as nanoreactors. Ultrasounds force the dissolution and the reaction stars. The products (alcohol, water and silanol) help to continue the dissolution, being catalyst content, temperature bath and alkyl group length dependent. Popular choices used in the preparation of silica-based gels are tetramethoxysilane (TMOS), Si(OCH3)4, and tetraethoxysilane (TEOS), Si(OC2H5)4. The resultant “sonogels” are denser gels with finer and homogeneous porosity than those of classic ones. They have a high surface/volume ratio and are built by small particles (1 nm radius) and a high cross-linked network with low –OH surface coverage radicals. In this way a cluster model is presented based on randomly-packed spheres in several hierarchical levels that represent the real sonoaerogel. Organic modified silicates (ORMOSIL) were obtained by supercritical drying in ethanol of the corresponding alcogel producing a hybrid organic/inorganic aerogel. The new material takes the advantages of the organic polymers as flexibility, low density, toughness and formability whereas the inorganic part contributes with surface hardness, modulus strength, transparency and high refractive index. The sonocatalytic method has proven to be adequate to prepare silica matrices for fine and uniform dispersion of CdS and PbS quantum dots (QDs), which show exciton quantum confinement. We present results of characterization of these materials, such as nitrogen physisorption, small angle X-ray/neutrons scattering, electron microscopy, uniaxial compression and nanoindentation. Finally these materials find application as biomaterials for tissue engineering and for CO2 sequestration by means the carbonation reaction.

Publisher

Trans Tech Publications, Ltd.

Subject

Mechanical Engineering,Mechanics of Materials,General Materials Science

Reference138 articles.

Cited by 8 articles. 订阅此论文施引文献 订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献

1. Aerogels Through Ultrasonically-Assisted Synthesis;Springer Handbook of Aerogels;2023

2. The Story of Aerogel;Springer Handbook of Aerogels;2023

3. The Sol-Gel Chemistry of Oxides from Alkoxides;Introduction to Sol-Gel Processing;2020

4. Aerogels Synthesis by Sonocatalysis: Sonogels;Aerogels Handbook;2011

5. History of Aerogels;Aerogels Handbook;2011

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