This chapter focuses on one of the most studied aerogel materials, silica aerogels. It aims at presenting a brief overview of the elaboration steps (sol–gel synthesis, aging, and drying), the textural and chemical characteristics (aggregation features, porosity, and surface chemistry), the main physical properties (from thermal, mechanical, acoustical, and optical, to biological, medical, etc.)...

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...

Introduction: Dust from comet Wild 2 was collected at a velocity of 6.1 km/s by the Stardust spacecraft using low-density silica aerogel [1]. During deceleration, dust particles fragmented, mixed with aerogel, and were thermally modified, often melted. In order to disentangle the properties of impacting cometary particles from those caused by the capture process, Wild 2 material from various lo...

Introduction: The NASA Stardust mission is expected to collect in low-density, silica aerogel more than 1,000 dust particles >10 μm in size from the dust coma surrounding Comet Wild-2. It is planned that Stardust will return these samples to Earth early in 2006. Removal of each particle from the aerogel increases the possibility of contamination or loss, thus we are developing a facility to per...

Silica aerogels are materials well suited for high power nonlinear optical applications. In such regime, the non-trivial thermal properties may give rise to the generation of optical shock waves, which are also affected by the structural disorder due to the porous solid-state gel. Here we report on an experimental investigation in terms of beam waist and input power, and identify various regime...

Superfluid 3He confined in aerogel offers a unique chance to study the effects of a short mean free path on the properties of a well defined superfluid Fermi liquid with anisotropic pairing. Transport coefficients and collective excitations, e.g. longitudinal sound, are expected to react sensitively to a short mean free path and to offer the possibility for testing recently developed models for...

Developing a novel and facile way to synthesize composite aerogels plays an important role in the applications of aerogels. UV-resistant hydrophobic titania-containing silica aerogels are prepared for the first time using potassium titanate as precursor by a modified ambient pressure drying method. The well established silica-titania networks, which can be tuned from 10 to 30 nm by adjusting th...