From radial to unidirectional water pumping in zeta-potential modulated Nafion nanostructures

Abstract

Chemically propelled micropumps are promising wireless systems to autonomously drive fluid flows for many applications. However, many of these systems are activated by nocuous chemical fuels, cannot operate at high salt concentrations, or have difficulty for controlling flow directionality. In this work we report on a self-driven polymer micropump fueled by salt which can trigger both radial and unidirectional fluid flows. The micropump is based on the cation-exchanger Nafion, which produces chemical gradients and local electric fields capable to trigger interfacial electroosmotic flows. Unidirectional pumping is predicted by simulations and achieved experimentally by nanostructuring Nafion into microarrays with a fine tune modulation of surrounding surface zeta potentials. Nafion micropumps work in a wide range of salt concentrations, are reusable, and can be fueled by different salt cations. We demonstrate that they work with the common water-contaminant cadmium, using the own capture of this ion as fuel to drive fluid pumping. Thus, this system has potential for efficient and fast water purification strategies for environmental remediation. Unidirectional Nafion pumps also hold promise for effective analyte delivery or preconcentration for (bio)sensing assays.

An Efficient Ambient‐Moisture–Driven Wearable Electrical Power Generator

“…Nafion is a proton‐selective layer and provides a platform for H + transport, while modified fluorinated Nafion (F‐Nafion ) exhibits enhanced electronegativity and enhanced driving force for proton transport. [ 16 ] PDDA serves as a source of mobile electronegative Cl − ions. Thus, the (GO)PANI composite generates the positive charge carrier (H + ) and forms the cathode, while the F‐Nafion (PDDA) component provides free negative ions (Cl − ) and forms the anode part of the MODEG.…”

“…The highly conductive anode and cathode layers produce a potential difference owing to oppositely directed diffusion of positively charged H + ions from the (GO)PANI layer and negatively charged Cl − ions from the F-Nafion (PDDA) layer. [15,16] We show here that series and parallel combinations of our MODEG units can provide sufficient power to drive commercial electronic devices. To illustrate the practical value of our system, we embedded (GO)PANI:F-Nafion (PDDA) hybrid film in a mask; this setup consistently generated 450-600 mV from exhaled water vapor during usual breathing, and provided sufficient power for practical applications.…”

“…The highly conductive anode and cathode layers produce a potential difference owing to oppositely directed diffusion of positively charged H + ions from the (GO)PANI layer and negatively charged Cl − ions from the F‐Nafion (PDDA) layer. [ 15,16 ]…”

Harnessing the Waste-to-Wealth Potential of Saraca asoca Plant-Derived Nanoparticles for the Sustainable Removal of Cationic Dyes through Regenerative Adsorption

“…In contrast, a low or negative zeta potential can lead to particle aggregation and precipitation. 39 From the analysis of SANPs, shown in the inset of Figure 2, the average zeta potential value was found to be 55 mV, which indicates that the particle is stable.…”

Bioresource Upgrade for Sustainable Energy, Environment, and Biomedicine

“…The research of artificial self-propelling micro/nanomotors has rapidly developed in last few decades [ 296 , 297 ]. Several advanced developments and excellent contributions have been made in this field.…”