Shape memory conductive electrospun PVA/MWCNT nanocomposite aerogels

Abstract

Shape memory polymers have promising applications in different fields. In this work, polyvinyl alcohol/multiwall carbon nanotube nanocomposite aerogels were fabricated through supercritical CO2 drying of electrospun hydrogel counterparts. Mercury porosimetry measurements and scanning electron microscopy results indicated that the nanofibrous aerogel had a high porosity (more than 80%), low density (0.025–0.036 g cm−3), high surface area (more than 1700 m2 g−1) and a pore size less than 100 nm. By incorporating multiwall carbon nanotubes, the density and Young’s modulus of the polyvinyl alcohol/multiwall carbon nanotube nanocomposite aerogel were increased up to 0.03 g cm−3 and 38 MPa, respectively. A percolation threshold of 1.5 wt% of the multiwall carbon nanotube was achieved for the conductive polyvinyl alcohol/multiwall carbon nanotube nanocomposite aerogel. The nanofibrous aerogel showed a perfect shape memory effect under thermal stimulus, and the corresponding results revealed that the shape recovery ratio and recovery speed of the nanocomposite aerogel were significantly higher than pure polyvinyl alcohol aerogel owing to the stabilizing of the crystalline domains and improvements in mechanical properties due to the presence of the multiwall carbon nanotubes. PVA/MWCNT nanocomposite aerogels were fabricated via the ScCO2 drying method. The aerogels were fully characterized, and their shape memory behaviors were examined. As the MWCNT content was increased, the electrical conductivity increased abruptly by up to 4 orders of magnitude, implying that an electrical percolation network had formed in the nanocomposite aerogels. The shape memory results illustrated the shape recovery ratio, and the recovery speed of the nanocomposite aerogels increased, due to the addition of the MWCNTs.