Synthesis and Conductivity of Multiwalled Carbon Nanotubes Modified Poly(Vinyl Alcohol)/Poly(Diallyldimethylammonium Chloride) as Alkaline Anion-Exchange Membranes

A new type of cross-linked polymer blend membranes consisting of poly(vinyl alcohol) (PVA), poly(diallyldimethylammonium chloride) (PDDA) and multiwalled carbon nanotubes (MWCNTs) have been prepared and evaluated as anion conducting polymer electrolytes. In particular, the anion conductivity (OH-) and water uptake of PVA/PDDA membranes modified with different structures’ MWCNTs were investigated, ie., MWCNTs-COOH, MWCNTs-OH and pristine MWCNT. It is found that the conductivity and water uptake of PVA/PDDA membrane both decreased with addition of 1 wt.% MWCNTs. However, the presence of MWCNTs played an important role in cutting down water uptake. The OH- conductivities were all gradually increased with increasing temperature, where the maximum OH- conductivity of 0.0166 S cm-1 was obtained for PVA/PDDA/MWCNTs at room temperature, and increased with temperature up to 80oC.