CONTEXT

Carbon aerogels are highly porous structures which show a very low apparent density. They are generally produced by « templating » methods where a 3D structure is used as a template impregnated by carbon/carbon precursor to give the required geometry. Such materials may have applications in composites, noise insulation, vibration damping. Nevertheless carbon aerogels are quite inadequate to well known aerogel applications like separation and liquid/solid filtration because there is a balance to found between speed o filtration (large pores) and efficiency.

TECHNICAL DESCRIPTION

This is one aim of the invention to provide a new family of aerogels which pore distribution allows an efficient filtration at interesting speed. CNTs are dispersed in water with a surfactant (generally ionic) and then a foaming agent is added in presence of a gas. The foam is freezed dried to eliminate water. An ultimate thermal treatment can be applied to the obtained material in order to carbonate the foaming agent and surfactant or (depending on temperature)  to mechanically reinforce the structure. The aerogel produced show a « macro porosity » which mean dimension is 40 µm or more (generally comprised between 50 microns and 600 microns) and a « super meso porosity » in the walls of the macro pores which mean dimension is smaller than 60nm). Apparent density of such materials lies in the order of 0.2 g/cm3; pore and specific surface area 35m2/g.

BENEFITS

• -Ultra low density, high surface area
  -Cheap process
  -No manipulation of « as produced CNT

  INDUSTRIAL APPLICATIONS

• -Catalysis
  -Storage of non wetting liquid (fuel cells)
  -Filtration (biological agents like blood)
  -Membranes for waste water (chemical or bacteriological) decontamination
  -Chromatographic column
  -Substrate for biomaterial growth (bones)

DEVELOPMENT STAGE

Aerogels are available.