Electrically conductive aerogels composed of cellulose and carbon nanotubes

Aerogels composed of carbon nanotubes (CNTs) and cellulose were fabricated by the flash freezing/lyophilization process using wet-gel precursors, which were regenerated from a homogeneous dispersion of CNTs and cellulose in alkaline-urea aqueous solution. The morphology and textural properties of the resultant composite aerogels were investigated by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and nitrogen adsorption-desorption tests. All the prepared materials exhibited both a nanostructured solid network (specific surface areas between 140 and 160 m(2) g(-1)) and a nanoporous network (including macropores, mesopores and micropores). The results from thermogravimetric analysis and tensile tests revealed that the composite aerogels have good thermal stability and excellent mechanical properties, respectively. The Young's modulus of the composite aerogels could be tuned to reach about 90 MPa. And composite aerogels with 3-10 wt% CNTs have a conductivity of about 2.3 x 10(-4) to 2.2 x 10(-2) S cm(-1), with the conductivity threshold at MWCNT volume fractions being as low as 3 x 10(-3). Furthermore, these cellulose-CNT composite aerogels showed good sensitivity to ambient pressure.