A novel method for fabricating polyelectrolyte complex/inorganic nanohybrid membranes with high isopropanol dehydration performance

Polyelectrolyte complexes (PECs) nanohybrid membranes prepared via traditional methods have not been reported due to the insolubility and infusibility of PECs. In this study, a novel method for fabricating PEC-based nanohybrid membranes filled with both SiO2 (globule) and multiwall carbon nanotubes (MWCNTs, linear) is proposed. Five types of PEC/SiO2 nanohybrids were prepared and the incorporation of SiO2 nanoparticles into PEC matrixes was followed by ζ potential and optical transmittance. Structures of PEC/SiO2 nanohybrids were characterized by FT-IR, transmission electron microscopy (TEM) and field emission electron scanning microscopy (FESEM). SiO2 is proved to be uniformly dispersed in PEC matrix at single nanoparticles level. Importantly, the incorporation of SiO2 enhances the processability of pristine PECs, i.e., some insoluble PECs turn soluble in NaOH after the incorporation of SiO2 nanoparticles. Mechanical properties of CMCNa-PDDA PEC/SiO2 nanohybrid membranes are improved and five PEC/SiO2 nanohybrid membranes all show high pervaporation performance in isopropanol dehydration. Moreover, PEC/MWCNTs nanohybrid films were prepared in the same method and FESEM shows that MWCNTs are evenly dispersed in the PEC matrix mainly at a single MWCNT level. Note that the fine dispersion of both SiO2 and MWCNTs in PEC matrix cannot be achieved by direct blending PEC with SiO2 or MWCNTs.