Successful new aerogels
Aerogels have been known to change the world of new materials in the field of civil aerospace, defense and other high-tech fields and construction, industrial pipe insulation, etc. have a very wide range of applications. Structurally, theis zero-dimensional quantum dots, one-dimensional or two-dimensional nanowire films such as low-dimensional nano-structure three-dimensionally assembled nanoporous ultra-light material. Low-dimensional structures of various variables, such as geometry, size, density, surface topography, chemical properties and other parameters, will have a significant impact on the final properties of the obtained airgel. So far, a variety of low-dimensional structures can be assembled into different airgel, but the size of these nanostructured elements are less than 100 nanometers, or even just a few nanometers. Preparation of structural unit is greater than the size of 100 nm for great challenges airgel, which is mainly caused by two reasons: First, the larger the size of the airgel structure unit, which is smaller specific surface area. The structural unit of submicron order, whether organic or inorganic, the specific surface area of the obtained aerogels are very small, thus losing the excellent characteristics airgel large surface area; the second is whether nanoscale structural units connection between the chemical bonding or physical action, as the structural unit size becomes larger, the proportion of the total number of atoms at a drastically reduced atom thus assembled will airgel material as a structural unit becomes large in size and sharp brittle. , Led the team with airgel professor, University of London and University of Science and Technology of China Song Wenhui, Professor Yan Lifeng, etc. To solve the above problems of Nano Technology and Nano-bionics researcher at the Institute of Chinese Academy of Sciences Zhang same, with an average diameter of 220 nm conductive polymer hollow ball is a precursor to graphene oxide crosslinker, successively by a sol – gel process, supercritical fluid extraction step of the key processes, like high-temperature heat treatment process, successfully obtained a novel all-carbon aerogels, graphite i.e. alkenyl carbon hollow spheres cross-linked aerogels. Graphene crosslinking agent is present, the point between the ball and the ball contact point in contact across cleverly converted, thus improving the mechanical properties of the final airgel; using hollow spheres, and hollow spheres submicron in shell create a large number of micropores on, to ensure that the ultimately obtained airgel has a large specific surface area; conductive polymer precursor is selected such that the final all-carbon airgel achieved element doped with nitrogen. Graphene crosslinked carbon hollow spheres having a low density aerogels obtained study, high conductivity, high specific surface area, high Young\’s modulus, and many other superiorPoint, the expected energy, sensing, catalysis, adsorption, separation, field of functional composite materials have been widely used. For example, carbon airgel balloons crosslinked graphene as an electrode material used in a chemical-type thermoelectric output U- pool, the battery up to 1.05 W · m-2 (6.4 W · Kg-1), which is relatively Kano cyclic energy conversion efficiency as high as 1.4%, these values are far higher than the value of the same type of device. The work is assembled into a large airgel particles provides a good design ideas to solve the problem of sub-micron structural units airgel preparation of functional techniques.