pH-dependent water penetration through CNT sub-layers arranged on the polycarbonate membrane filters

A carbon nanotube (CNT) membrane that included fragments of buckypaper and aligned nanotube forests was produced from industrial single-walled CNTs functionalized with carboxyl functional groups and a polycarbonate membrane substrate. Water penetration measurements demonstrated the flow rate dependence on the pH of the solution. This phenomenon is a consequence of the specific membrane structure and can be exploited to control liquid flow in a variety of processes.