Thermo-Responsive Polyethersulfone Composite Membranes Blended with Poly(N-isopropylacrylamide) Nanogels

Thermo-responsive composite polyethersulfone (PES) membranes blended with monodisperse poly(N-isopropylacrylamide) (PNIPAM) nanogels were prepared from blends of PES solution and PNIPAM nanogels by phase inversion. The monodisperse and spherical PNIPAM thermo-responsive nanogels were synthesized by precipitation polymerization. The blended PNIPAM nanogels did not affect the formation of the finger-like pore structure of the PES membrane but resulted in microporous structures. The water flux across the composite membrane at temperatures above the lower critical solution temperature (LCST) of PNIPAM was much higher than that below the LCST because of thermo-responsive shrinking/swelling of the PNIPAM nanogels, and the thermo-responsive permeation characteristics were affected by the content of blended PNIPAM nanogels. The thermo-responsive permeation performance of the composite membranes was reversible and reproducible.