Positively K⁺‐Responsive Membranes with Functional Gates Driven by Host–Guest Molecular Recognition

Abstract

A novel positively K+‐responsive membrane with functional gates driven by host‐guest molecular recognition is prepared by grafting poly(N‐isopropylacrylamide‐co‐acryloylamidobenzo‐15‐crown‐5) (poly(NIPAM‐co‐AAB15C5)) copolymer chains in the pores of porous nylon‐6 membranes with a two‐step method combining plasma‐induced pore‐filling grafting polymerization and chemical modification. Due to the cooperative interaction of host‐guest complexation and phase transition of the poly(NIPAM‐co‐AAB15C5), the grafted gates in the membrane pores could spontaneously switch from “closed” state to “open” state by recognizing K+ ions in the environment and vice versa; while other ions (e.g., Na+, Ca2+ or Mg2+) can not trigger such an ion‐responsive switching function. The positively K+‐responsive gating action of the membrane is rapid, reversible, and reproducible. The proposed K+‐responsive gating membrane provide a new mode of behavior for ion‐recognizable “smart” or “intelligent” membrane actuators, which is highly attractive for controlled release, chemical/biomedical separations, tissue engineering, sensors, etc.

Plasmonic Retrofitting of Membrane Materials: Shifting from Self‐Regulation to On‐Command Control of Fluid Flow

“…[1][2][3][4][5] This is justified by the unparalleled degree of flow control exhibited by the pore-forming proteins constituting the ion and water channels in living organisms. This switchable feature, better known as "gating", usually comprises the entire sequence of events from sensing the stimulus (e.g., temperature, voltage, pressure, or presence of ligands) to transducing that signal, which www.advmat.de www.advancedsciencenews.com Examples of these units include synthetic polymers endowed with macrocyclic structures (such as cyclodextrins [17] or crown ethers [18] ), antibodies, [19] enzymes, [20] aptamers, [21] peptides, [22] or boronic acids. This switchable feature, better known as "gating", usually comprises the entire sequence of events from sensing the stimulus (e.g., temperature, voltage, pressure, or presence of ligands) to transducing that signal, which www.advmat.de www.advancedsciencenews.com Examples of these units include synthetic polymers endowed with macrocyclic structures (such as cyclodextrins [17] or crown ethers [18] ), antibodies, [19] enzymes, [20] aptamers, [21] peptides, [22] or boronic acids.…”

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

“…Furthermore, while cross‐linked hydrogel networks or microspheres are employed as functional materials, the extent of swelling/shrinking of these materials is limited due to the restricted 3D network space. It is reported that Chu and coworkers developed a novel K + ‐responsive smart membrane with a responsive coefficient of up to 54 times through grafting functional macromolecular chains onto nylon‐6 membrane substrates …”

A Novel Poly(N‐Isopropylacrylamide‐co‐acryloylamidobenzo‐12‐crown‐4) Microgel with Rapid Stimuli‐Responsiveness for Molecule‐Specific Adsorption of γ‐Cyclodextrin

“…Here, we report a novel poly( N ‐isopropylacrylamide‐ co ‐acryloylamidobenzo‐12‐crown‐4) (PNB) microgel as guest molecule adsorbent to selectively respond to γ‐CD with rapid responsive characteristics. The microgels are synthesized by a two‐step reaction method ( Figure ) . First, poly( N ‐isopropylacrylamide‐ co ‐acrylic acid) (PNA) microgels are synthesized by precipitation copolymerization, and then the microgels are further modified by benzo‐12‐crown‐4 (B 12 C 4 ) units via condensation reaction.…”