Structure and properties of multi-walled carbon nanotube porous sheets with enhanced elongation

In this article, multi-walled carbon nanotubes (MWNTs)/dodecyl benzene sulfonic acid (DBSA) porous sheet networks (PSNs) of enhanced extensibility were developed and characterized. The MWNT/DBSA networks possess failure strains of 8-12 %, markedly higher than the literature reported values of 0.5-4 %. The networks were prepared through micro-filtration of highly dispersed MWNT in DBSA aqueous solutions. The DBSA molecule has two functions: In the dispersion stage, DBSA functions as a dispersant leading to the establishment of stable individually dispersed MWNT, and in the MWNT porous sheet, the presence of DBSA within the nanotubes' network creates a lubrication-like effect, enhancing the networks' extensibility. In fact, it was found that DBSA is assembled in two modes within the nanotubes' network: a fraction which is strongly adsorbed onto the CNT surface, and another fraction entrapped within the network as a DBSA/water solution. It should be noted that the composition of these systems is stable under ambient room temperature conditions. Comparison of MWNT networks prepared from the MWNT/DBSA dispersions and from the same but coagulated before filtration has shown superiority of the non-coagulated systems in relation to structure and mechanical properties. The prepared MWNT/DBSA PSNs of enhanced extensibility were developed without any modification by polymers, and they are characterized by high electrical conductivity and nano-porosity.