Proton‐Gated Rectification Regimes in Nanofluidic Diodes Switched by Chemical Effectors

Abstract

During the last decade, nanofluidic devices based on solid-state nanopores and nanochannels have come into scene in materials science and will not leave anytime soon. One of the main reasons for this is the excellent control over ionic transport exerted by such devices that promises further important advances when integrated into more complex molecular devices. As a result, pH, temperature, and voltage-regulated devices have been obtained. However, nowadays, there is still a necessity for molecule-driven nanofluidic devices. Here, a sugar-regulated pH-responsive nanofluidic diode is presented obtained by surface modification of conical polycarbonate nanochannels with electropolymerized 3-aminophenylboronic acid. Control over the ionic transport has been achieved by a successful decoration of asymmetric nanochannels with integrated molecular systems. The as-synthesized boronate-appended zwitterionic polymer exhibits an acid-base equilibrium that depends on the concentration of sugar, which ultimately acts as a chemical effector setting different pH-dependent rectification regimes. As a result, the same nanodevice can perform completely different proton-regulated nanofluidic operations, i.e., anion-driven rectification, cation-driven rectification, and no rectification, by simply varying the concentration of fructose in the electrolyte solution.

Track‐Etched Nanopore/Membrane: From Fundamental to Applications

“…The same principles by using polyampholytes to design pH‐responsive ion channels were widely reported by several groups for PC conical nanopores. [ 196,197 ] The amphipol containing carboxylic acids and tertiary amines was immobilized on the tip side of conical nanopore, which was previously coated by a gold layer. [ 197 ] Positive charges of amines in acidic condition give the pore selectivity to anions.…”

“…[ 196,197 ] The amphipol containing carboxylic acids and tertiary amines was immobilized on the tip side of conical nanopore, which was previously coated by a gold layer. [ 197 ] Positive charges of amines in acidic condition give the pore selectivity to anions. Conversely, negative charges of carboxylic acid in basic solution makes the nanopore selective to cations.…”

Molecular Design of Solid‐State Nanopores: Fundamental Concepts and Applications

“…In a completely different modification approach, the introduction of boronic moieties to a nanofluidic system was performed by electropolymerization of 3‐aminophenylboronic acid on Au‐sputtered conical track‐etched polycarbonate nanochannels . The binding of sugar was used as a chemical effector inducing significant p K a shifts in the boronic moieties of the poly(aminophenylboronic acid) (PAPBA).…”

“…b) Mechanism of the effect of the sugar on the acid–base equilibrium and the iontronic responsiveness. a,b) Reproduced with permission . Copyright 2018, American Chemical Society.…”

Nanofluidic osmotic power generators – advanced nanoporous membranes and nanochannels for blue energy harvesting

“…28,29 Motivated by the fascinating properties of biological ion channels and exploiting the concept of "learning from nature", the creation of platforms based on solid-state nanochannels (SSNs) has attracted the attention of the scientic community. [30][31][32][33][34][35][36][37][38] In this scenario, the development of membrane-containing SSNs appeared as promising components for energy harvesting systems. [39][40][41][42] The immense potential of the combination of nanotechnology and energy-related applications rapidly captured the attention of the scientic community causing full and continuous progress in the eld of nanoporous membrane-based energy harvesting.…”