Electro‐responsive semi‐IPN hydrogel with enhanced responsive property for forward osmosis desalination

Abstract

An electro‐responsive hydrogel with semi‐interpenetrating polymer networks (semi‐IPN) composed of crosslinked poly(2‐acrylamido‐2‐methyl‐l‐propanesulfonic acid‐co‐acrylamide) (P(AMPS‐AM)) and linear polyelectrolyte polyacrylic acid (PAA) was explored. The semi‐IPN hydrogel was characterized with different methods and then used as advanced draw agent toward high water recovery for forward osmosis (FO) desalination. The swelling kinetics of the semi‐IPN hydrogel was investigated, and the electro‐responsive nature of the hydrogel under electric stimulus (in direct contact with electrodes) was determined. Results indicated that in comparison with pure P(AMPS‐AM) hydrogel, the semi‐IPN hydrogel exhibited a loose network structure with more pores. In addition, a higher equilibrium swelling capacity and more pronounced deswelling under electric stimulus can be observed for the semi‐IPN hydrogel. Furthermore, the semi‐IPN hydrogel displayed a similar initial water flux of 2.20 L m−2 h−1 (LMH) from 2 g/L NaCl solution of a lab‐scale FO process. Importantly, the semi‐IPN hydrogel had a 25% increase in water recovery efficiency under the electric stimulus of 15 V, and showed better recyclability during three cycles of regeneration compared with pure P(AMPS‐AM). The mechanism of enhanced dewatering nature for the semi‐IPN hydrogel under electric stimulus was elucidated. These results indicate this new hydrogel's potential as a promising candidate for improving FO performance.

PVA–PNIPAM Hydrogel-Based Moisture-Electric Generators with Tunable Pore Structures for Enhanced Power Generation

“…This special layered porous structure could enlarge the interface between the hydrogel and moist air, increasing the availability of water capture sites . Modulating the hydrogel network can control how water exists, and details will be analyzed below. − …”

Preparation and Properties of PDMS Surface Coating for Ultra-Low Friction Characteristics

“…Under ideal conditions, the coating and the substrate will present a whole state, which can effectively prevent the coating from falling off and substrate separation. Moreover, during the UV curing process, the carbon–carbon double bond (CC) of AM and that of AMPS are polymerized to form AM/AMPS binary copolymer. − With the increase of curing time, the monomer migrates to the surface of the substrate to form a coating, and the two monomers react with each other to form a copolymer. − However, as the concentration of AMPS increases, the curing rate of the monomer solution also increases, the cross-linking density of the binary copolymer increases after curing, , and the migration ability of the monomer in the solution decreases, directly resulting in a decrease in the roughness and thickness of the as-prepared coating.…”

“…63−65 With the increase of curing time, the monomer migrates to the surface of the substrate to form a coating, and the two monomers react with each other to form a copolymer. 66−68 However, as the concentration of AMPS increases, the curing rate of the monomer solution also increases, the cross-linking density of the binary copolymer increases after curing, 69,70 and the migration ability of the monomer in the solution decreases, directly resulting in a decrease in the roughness and thickness of the as-prepared coating.…”

Interpenetrating polymer networks for desalination and water remediation: a comprehensive review of research trends and prospects

“…These results indicate that the proposed hydrogel has the potential for improving FO performance. 74 Cai and his team designed thermally responsive semi-IPN hydrogels and were used as a draw agent in FO systems. The semi-IPN hydrogel showed good balance between thermally responsive swelling and dewatering behavior.…”