Nanostructure and optical transparency of silica aerogels

Emmerling, A.; Wang, P.; Popp, G.; Beck, Andreas; Fricke, J.

doi:10.1051/jp4:1993873

Cited by 6 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For most applications a high optical transmission is desirable; therefore, numerous attempts were made to influence the optical properties. Improvements were achieved by physical approaches such as desorption of water, different drying procedures, and adjusting the synthesis conditions [4], [177], [225][226][227][228][229][230][231][232].…”

Section: Optical Propertiesmentioning

confidence: 99%

Aerogels

Hüsing

Schubert

2006

Ullmann's Encyclopedia of Industrial Chemistry

View full text Add to dashboard Cite

The article contains sections titled: 1. Introduction 2. Synthesis 2.1. Network Formation and Structure 2.1.1. Inorganic Aerogels 2.1.1.1. SiO 2 Aerogels 2.1.1.2. Metal Oxide Aerogels 2.1.2. Inorganic/Organic Hybrid Aerogels 2.1.3. Organic Aerogels 2.2. Drying Methods 2.2.1. Supercritical Drying 2.2.1.1. Drying in Organic Solvents 2.2.1.2. Supercritical Drying with CO 2 2.2.2. Freeze Drying 2.2.3. Ambient Pressure Drying 2.3. Modification of Aerogels after Drying 3. Properties 3.1. Structural Properties 3.2. Physical and Chemical Properties 3.2.1. Optical Properties 3.2.2. Mechanical and Acoustic Properties 3.2.3. Thermal Conductivity 3.2.4. Hydrophobicity 4. Applications 4.1. Çerenkov Detectors 4.2. Thermal Insulation 4.3. Catalysis 4.4. Application as Storage Media 4.5. Electrical and Electronic Applications 4.6. Acoustic and Mechanical Applications 4.7. Optical Applications 4.8. Other Applications 5. Future Perspectives Aerogels are unique among solid materials. They have extremely low densities (up to 95 % of their volume is air), large open pores, and a high inner surface area. This combination of properties results in interesting physical properties, e.g., for silica aerogels extremely low thermal conductivities and low sound velocities are combined with optical transparency. Aerogels are typically prepared via wet chemical processes, such as sol – gel processing, and thus their pore system is initially filled with liquid. Only special drying techniques allow for exchange of the pore liquid against air while maintaining the filigrane solid framework. The most common drying technique is supercritical extraction, and sometimes chemical modification of the inner surface can be used to facilitate drying. The structure of the gel network, and thus the physical properties of aerogels, decisively depends on the choice of the precursors and the chemical reaction parameters for preparing the gels. Therefore, the later materials properties can be deliberately designed in the starting reaction solution.

show abstract

Section: Optical Propertiesmentioning

confidence: 99%

Aerogels

Hüsing

Schubert

2006

Ullmann's Encyclopedia of Industrial Chemistry

View full text Add to dashboard Cite

show abstract

“…For the X-ray scattering experiments as well as for the optical investigations $1 mm thick slices were cut from the monolithic aerogel block with a diamond saw. The USAXS pattern I(q) was evaluated with a combination of a fractal structure factor S(q), a particle structure factor F(q), and a term that describes the packing of the fractal clusters U(q) [8,9]:…”

Section: Sample Preparation and Characterizationmentioning

confidence: 99%

Switching silica aerogels from transparent to opaque

Reichenauer

Fricke

Manara

et al. 2004

Journal of Non-Crystalline Solids

Self Cite

View full text Add to dashboard Cite

“…The combination of magnetic and elastic properties leads to various phenomena which can be initiated by the external magnetic field [1][2][3][4][5][6][7]. These phenomena have opened up new possibilities for technological applications, such as: 1) magnetoelastic composites; with particles made of magnetostrictive hard or soft ferromagnetic material; 2) magnetorheological elastomers, for applications in the aerospace and automotive industries as actuators on antifriction components; 3) heat-shrinkable elastic ferromagnets with variable magnetic and conductive properties.…”

Section: Introductionmentioning

confidence: 99%

Microstructure of stomaflex based magnetic elastomers

et al. 2010

View full text Add to dashboard Cite

Stomaflex elastomers filled with two types of magnetic particles (nano-and micro-sized) were investigated. It was observed that doping with Fe 3 O 4 nanoparticales and applying a magnetic field during the polymerisation process led to a significant change in the local structure of the elastomer. Decreases in the quasi-crystalline phase concentration, in the average size of the crystalline blocks, and in the ordering distance were observed after doping the elastomer with magnetite nanoparticles. After filling the polymer with Fe 3 O 4 nanoparticles, yet the elastomer fractal dimension changes. For the elastomer filled with a large amount of Fe microparticles (75% particle concentration) a texture effect is observed, and this effect is larger for the samples polymerised in a magnetic field. At all microparticle concentrations, these elastomers exhibit surface fractal structure.

show abstract

Nanostructure and optical transparency of silica aerogels

Cited by 6 publications

References 0 publications

Aerogels

Aerogels

Switching silica aerogels from transparent to opaque

Microstructure of stomaflex based magnetic elastomers

Contact Info

Product

Resources

About