Improving the Separation Performance of Nanocomposite Membrane By Aligning Carbon Nanotubes Into Polymeric Matrix

The nanocomposite membranes containing carbon nanotubes (CNTs) have shown better separation performance than the bare membranes. For example, several studies have demonstrated that a higher permeation flux can be obtained by incorporating functionalized CNTs in the polymeric membrane. However, the improvement in separation performance is limited due to the disordered state of CNTs in the nanocomposite membranes.

In this work, a facile method, hot-press combined with peel-off (HPPO), is established, through which CNTs can be successfully vertically aligned on the polymeric membrane substrate. Shear force and mechanical stretch are proposed to be the main forces to align the tubes perpendicular to the substrate surface during the peel-off process. The TEM images show that the alignment of CNTs keeps their orientation in a thin hybrid membrane by coating polymer casting solution. The stable alignment of CNTs by HPPO greatly contributes to the improved separation performance of the nanocomposite membranes. The CNTs facilitate the permeation of components due to their nature molecular channel and the microvoids between the polymer matrix and tubs.