Engineered Asymmetric Heterogeneous Membrane: A Concentration-Gradient-Driven Energy Harvesting Device

Abstract

Engineered asymmetric membranes for intelligent molecular and ionic transport control at the nanoscale have gained significant attention and offer prospects for broad application in nanofluidics, energy conversion, and biosensors. Therefore, it is desirable to construct a high-performance heterogeneous membrane capable of coordinating highly selective and rectified ionic transport with a simple, versatile, engineered method to mimic the delicate functionality of biological channels. Here, we demonstrate an engineered asymmetric heterogeneous membrane by combining a porous block copolymer (BCP) membrane, polystyrene-b-poly(4-vinylpyridine) (PS48400-b-P4VP21300), with a track-etched asymmetric porous polyethylene terephthalate membrane. The introduction of chemical, geometrical, and electrostatic heterostructures provides our heterogeneous membrane with excellent anion selectivity and ultrahigh ionic rectification with a ratio of ca. 1075, which is considerably higher than that of existing ionic rectifying systems. This anion-selective heterogeneous membrane was further developed into an energy conversion device to harvest the energy stored in an electrochemical concentration gradient. The concentration polarization phenomenon that commonly exists in traditional reverse electrodialysis can be eliminated with an asymmetric bipolar structure, which considerably increases the output power density. This work presents an important paradigm for the use of versatile BCPs in nanofluidic systems and opens new and promising routes to various breakthroughs in the fields of chemistry, materials science, bioscience, and nanotechnology.

Harnessing ‘Blue energy’: A Review on Techniques and Preliminary Analysis

“…In [14], besides evaluating performance of commercially available membrane, they had tested a tailor made membrane with significant reduction in resistance and achieved 1.3 W/m 2 . More recent type of membrane was reported such as pore-filling ion exchange membranes with open area spacer that achieved 2.4 w/m 2 [15], asymmetric heterogeneous membrane [16] which can be applied in nanofluidic application and membrane with chevron corrugation that reduce the pressure drop is able to produce up to 0.89w/m 2 . Works on modelling and simulation of RED process including the cell pair model based on thermodynamic and transport equation was proposed by Veerman [17].…”

Multipore membranes with nanofluidic diodes allowing multifunctional rectification and logical responses

“…In principle, this rectification could be enhanced by modifying the central compartment characteristics and controlling the pore tip shape and the nature and distribution of the pHsensitive groups. 12,23,31 We use a three-compartment electrochemical cell and two multiporous membranes with conical nanopores arranged in series. The membrane functionality is based on the pH-reversed ion current rectification and does not require specific surface functionalizations.…”

Smart Bioinspired Nanochannels and their Applications in Energy‐Conversion Systems

“…These heterogeneous membranes can respond to both single and multiple stimuli, offering important guidance for the use of functional BCPs in nanofluidic science. [36] Our group has designed novel artificial asymmetric nanochannels based on mesoporous zeolite (MCM 41) and polyimide (PI) and investigated the ionic current behavior and rectifying characteristics of this system, both theo retically and experimentally (Figure 2e). [37] Recently, Gao and co workers fabricated organic-inorganic hybrid nanochannels [37] Copyright 2014, Royal Society of Chemistry.…”