Smart gating membranes with in situ self-assembled responsive nanogels as functional gates

Abstract

Smart gating membranes, inspired by the gating function of ion channels across cell membranes, are artificial membranes composed of non-responsive porous membrane substrates and responsive gates in the membrane pores that are able to dramatically regulate the trans-membrane transport of substances in response to environmental stimuli. Easy fabrication, high flux, significant response and strong mechanical strength are critical for the versatility of such smart gating membranes. Here we show a novel and simple strategy for one-step fabrication of smart gating membranes with three-dimensionally interconnected networks of functional gates, by self-assembling responsive nanogels on membrane pore surfaces in situ during a vapor-induced phase separation process for membrane formation. The smart gating membranes with in situ self-assembled responsive nanogels as functional gates show large flux, significant response and excellent mechanical property simultaneously. Because of the easy fabrication method as well as the concurrent enhancement of flux, response and mechanical property, the proposed smart gating membranes will expand the scope of membrane applications, and provide ever better performances in their applications.

A Novel Thermoresponsive Catalytic Membrane with Multiscale Pores Prepared via Vapor‐Induced Phase Separation

“…The PNIPAM nanogels in solution that has passed through the membrane under different transmembrane pressures have been detected by using dynamic light scattering (DLS) technique, and the results show that no nanogel is found in the permeant solution. Furthermore, the transmembrane water fluxes at both 20 and 39 °C keep unchanged even after keeping the membrane in water for 70 d . The results confirm that the PNIPAM nanogels assembled at the pore/matrix interfaces are stable enough to resist the experimental pressure and the nanogel gates remain intact in the operation processes.…”

“…The control PES membrane, PES membrane blended with PNIPAM nanogels (PES/PNG), and that blended with PNG@Ag nanogels (PES/PNG@Ag) are fabricated by the same process parameters during the VIPS processes, where the vapor temperature, relative humidity, and exposure time are chosen as 25 °C, 70% and 2 min, respectively. Based on our previous work, the membranes prepared at these process parameters are provided with the cellular pores decorated with PNIPAM nanogels, which exhibits the high thermoresponsive factor and medium water flux. The size and distribution of membranes pores are measured using a capillary flow porometer (Porolux 1000, Porometer, Germany) via the gas/liquid displacement method.…”

“…The as‐prepared Ag NPs loaded PNIPAM nanogels are abbreviated as PNG@Ag. By adjusting the process parameters during the VIPS process, the PNGs@Ag nanogels can decorate on walls of the interconnected cellular pores, which are constructed throughout the membrane thickness. This fabrication method is simple and can be easily scaled up for mass production of thermoresponsive catalytic membranes.…”

Ethanol‐Responsive Poly(Vinylidene Difluoride) Membranes with Nanogels as Functional Gates

“…Ying et al 13 prepared pH‐ and thermo‐responsive microfiltration membranes from blends of poly(acrylic acid)‐grafted PVDF (PAAc‐ g ‐PVDF) copolymer and PNIPAM homopolymer in N ‐methyl‐2‐pyrrolidone (NMP) solution by phase inversion in water at 25 °C. Because the membrane formation process such as liquid‐induced phase separation is very fast, e.g., within 1 s, the position and distribution of stimuli‐responsive polymeric domains in the membranes were difficult to be observed and controlled 21.…”

Reversible Self-Actuated Thermo-Responsive Pore Membrane

“…In these efforts, thermo-responsive678, magnetic9 and chemical species (ex. pH1011, ions12, and specific molecules1314) oriented actuations have been reported including thermo-responsive hybrid membranes815. In addition, there is a growing interest in biomimetics as ways of precise actuation of smart membrane structure so that they are more adaptable to the environment1617.…”