Zwitterionic Nanohydrogels–Decorated Microporous Membrane with Ultrasensitive Salt Responsiveness for Controlled Water Transport

Abstract

Highly sensitive responsiveness is vital for stimuli‐responsive membranes. However, it is a great challenge to fabricate stimuli‐responsive membranes with ultrahigh gating ratio (the ratio of the salt solution permeating flux to the pure water permeating flux) and high response speed simultaneously. In this work, a salt‐responsive membrane with an ultrahigh gating ratio is fabricated via a facile strategy by grafting zwitterionic nanohydrogels onto a poly(acrylic acid)‐grafting‐poly(vinylidene fluoride) (PAA‐g‐PVDF) microporous membrane. Due to the synergistic effect of two functional materials, PAA chains and zwitterionic nanohydrogels tethered on PAA chains, this stimuli‐responsive membrane exhibits an ultrasensitive salt responsiveness with a gating ratio of up to 8.76 times for Na+ ions, 89.6 times for Mg2+ ions, and 89.3 times for Ca2+ ions. In addition, such zwitterionic nanohydrogels–grafted PAA‐g‐PVDF (ZNG‐g‐PVDF) membranes exhibit very rapid responses to stimuli. The permeating flux changes swiftly while altering the feed solution in a continuous filtration process. The excellent salt‐responsive characteristics endow such a ZNG‐g‐PVDF membrane with great potential for applications like drug delivery, water treatment, and sensors.

A Salt Stimulus-Responsive Nanohydrogel for Controlled Fishing Low-Density Lipoprotein with Superior Adsorption Capacity

“…In the case of SiO 2 -NG350 and SiO 2 -NG350-CS nanoparticles, the new peak of CH 2 at 285.9 eV is obtained attributed to the grafting of the NG350. Another new peak of N–CO in SiO 2 -NG350 and SiO 2 -NG350-CS is observed at 288.2 eV due to the amidation reaction, which demonstrates the successful modification of NG350 and CS.…”

“…Among them, the zwitterionic polymer-based nanohydrogels have advantages including design flexibility and ease of functionalization and have attracted considerable attention in various fields, e.g., sensing, protein delivery, and therapy . Recently, salt-responsive zwitterionic nanohydrogels were developed, and their bulk is modulated in response to the external salt stimulus. , This responsiveness endows the material with great potential for pore size control and hydrophilicity/hydrophobicity tailoring.…”

“…30 Recently, salt-responsive zwitterionic nanohydrogels were developed, and their bulk is modulated in response to the external salt stimulus. 31,32 This responsiveness endows the material with great potential for pore size control and hydrophilicity/hydrophobicity tailoring.…”

Advancing Strategies of Biofouling Control in Water-Treated Polymeric Membranes

“…Zwitterionic polymers have also attracted extensive attention as a new generation of fouling resistant material in recent years [ 83 ]. The term “zwitterionic polymer” generally refers to the side chain containing both positive and negative charged units.…”

Recent Advances in Stimuli‐Responsive Commodity Polymers

“…This responsiveness also provides opportunities for liquid transport control, separation, and sensor developments. [ 54 ]…”