monolithic aerogels of high molecular weight polyethylene (mw= 3x106- 6x106 g/mol) have been prepared by solvent extraction with supercritical carbon dioxide from thermoreversible gels prepared in decalin. these low density and highly porous aerogels present an apparent porosity up to 90%. the aerogel morphology observed by scanning electron microscopy (sem) is characterized by spherulitic stru...

Silica aerogels functionalized with strongly fluorescent carbon quantum dots were first prepared and used for simple, sensitive, and selective sensing of NO2 gas. In the presence of ethanol, homemade silica aerogels with a large specific surface area of 801.17 m(2)/g were functionalized with branched polyethylenimine-capped quantum dots (BPEI-CQDs) with fluorescence quantum yield higher than 40...

The thermal conductivity of gas-permeated single-walled carbon nanotube (SWCNT) aerogel (8 kg m − 3 density, 0.0061 volume fraction) is measured experimentally and modeled using mesoscale and atomistic simulations. Despite the high thermal conductivity of isolated SWCNTs, the thermal conductivity of the evacuated aerogel is 0.025 ± 0.010 W m − 1 K − 1 at a temperature of 300 K. This very low va...

a novel composite adsorbent, silica aerogel activated carbon was synthesized by sol-gel process atambient pressure drying method. the composite was characterized by fourier transform infraredspectroscopy (ft-ir), scanning electron microscopy (sem), differential scanning calorimetry(dsc) and nitrogen adsorption / desorption isotherms (bet).in the present study, the mentioned adsorbent was used m...

Nano-porous silica aerogels are unique materials often having a high specific surface area, a high porosity (75-99%), a low thermal conductivity (0.01-0.03W/mK), and a low index of refraction. Because of their unique properties, aerogels have been extensively studied, not only for use as transparent thermal insulators but also as inter-metal dielectric materials, optical and acoustic applicatio...

Thermophones are highly promising for applications such as high-power SONAR arrays, flexible loudspeakers, and noise cancellation devices. So far, freestanding carbon nanotube aerogel sheets provide the most attractive performance as a thermoacoustic heat source. However, the limited accessibility of large-size freestanding carbon nanotube aerogel sheets and other even more exotic materials rec...

Lightweight materials that are both highly compressible and resilient under large cyclic strains can be used in a variety of applications. Carbon nanotubes offer a combination of elasticity, mechanical resilience and low density, and these properties have been exploited in nanotube-based foams and aerogels. However, all nanotube-based foams and aerogels developed so far undergo structural colla...

Improved electrically powered artificial muscles are needed for generating force, moving objects, and accomplishing work. Carbon nanotube aerogel sheets are the sole component of new artificial muscles that provide giant elongations and elongation rates of 220% and (3.7 x 10(4))% per second, respectively, at operating temperatures from 80 to 1900 kelvin. These solid-state-fabricated sheets are ...

Aerogels have numerous applications due to their high surface area and low densities. However, creating aerogels from a large variety of materials has remained an outstanding challenge. Here, we report a new methodology to enable aerogel production with a wide range of materials. The method is based on the assembly of anisotropic nano-objects (one-dimensional (1D) nanotubes, nanowires, or two-d...

Recently many nanoporous carbons have been synthesized using templating method. On the contrary, carbons can be applied as the template, because carbon can be gasified. Zeolite molecular sieves are crystalline porous solids with intricate pore and channel systems in the molecular size range of 0.3 to ~3 nm. They are widely used in industry as heterogeneous catalysts [1]. Although micropores of ...