Functionalized Carbon Nanotubes Reinforced Polymer Electrolyte Membranes Prepared by Surfactant-Assisted Casting for Fuel Cell Applications

Functionalized carbon nanotubes (CNTs)/Nafion (R) nanocomposite membranes prepared with the surfactant-assisted method are presented for fuel cell applications. Interlinking non-covalent bonding between CNTs with a surfactant is an advantage of a prepared nanocomposite by a solution casting method. 1 wt% of CNTs such as pristine CNTs (p-CNTs) and oxidized CNTs (ox-CNTs) were respectively reinforced into Nafion (R) membranes by adding different amounts of surfactant based on Nafion (R) polymer wt%. Cetyltrimethylammonium bromide (CTAB), sodium octylbenzene sulfonate (SOBS), sodium octylsulfonate (SOS) and Triton X-100 were successfully added to the prepared CNTs/Nafion (R) nanocomposite membranes with a solution casting method. Comparative analysis of the dispersion from the different surfactant treated CNTs/Nafion (R) membranes was investigated by optical microscopy. Phenyl-ring attached surfactants, such as CTAB and SOBS were effective on dispersion of CNTs in the nanocomposites while other surfactants, such as SOS and Triton X-100 had an adverse effect on CNTs dispersion. Well CNTs dispersed Nafion (R) nanocomposites resulted in reduced methanol uptake and improved thermal stability measured by thermogravimetric analysis. In addition, ion exchange capacity and water uptake values were investigated for the CNTs/Nafion (R) membranes for PEM fuel cell applications.