Cell Junction Proteins-Mimetic Artificial Nanochannel System: Basic Logic Gates Implemented by Nanofluidic Diodes

Inspired by communication modes of cell junction proteins, an artificial bichannel nanofluidic diode system was constructed and investigated to implement basic “AND” and “OR” logic gates in different connection modes. Input conditions were set as conducting and nonconducting states of each nanofluidic diode unit. Output results were set as response current of the system at rated voltage. Besides, nanofluidic diodes with different ionic permeabilities were connected in multiple modes, and different logic operation results were obtained. This novel logic device based on nanofluidic diodes provided a new approach to establish diverse stimuli-responsive signal processing networks and has prospect to obtain nanofluidic diode intelligence chips by integrating in large scale

Gap Confinement Effect of a Tandem Nanochannel System and Its Application in Salinity Gradient Power Generation

As an important nanofluidic device, an artificial ion nanochannel could selectively transport ions inside its nanoconfinement space and the surface charge of the pore wall. Here, confinement effects were realized by tandem nanochannel units, which kept their cascade gaps less than 500 nm. Within these gaps, ionic conductance was governed by the surface charge density of the channel unit. Cations could be sufficiently selected and enriched within this confined space, which improves the cation transfer number of the system. Therefore, the tandem nanochannel system could greatly improve the diffusion potential and energy conversion efficiency in the salinity gradient power generation process. Poisson–Nernst–Planck equations were introduced to numerically simulate the ionic transport behavior and confirmed the experimental results. Finally, the gap confinement effect was introduced in the porous cellulose acetate membrane tandem nanochannel system, and a high output power density of 4.72 W/m2 and energy conversion efficiency of 42.22% were achieved under stacking seven channel units

Geometric Tailoring of Macroscale Ti₃C₂T_<i>x</i> MXene Lamellar Membrane for Logic Gate Circuits

Constructing nanofluidic diode nanochannels with an asymmetric structure for logic gate circuits has attracted extensive research interests. Currently, the preparation of a geometrically asymmetric nanochannel relies on cost-effective material-processing methods and has been hard to scale up, limiting the development of nanofluidic research. Herein, we introduce the idea of geometric tailoring to cut the MXene lamellar membrane in different shapes and investigate the ion transport behavior systematically. The ion rectification can be regulated by adjusting geometric factors such as the asymmetric ratio and height of the trapezoidal membrane. On the basis of the above-mentioned research on rectification characteristics, we further optimized the trapezoidal membrane into a triangular membrane on the macroscopic level and successfully applied it to logic circuits, realizing the logic operations of “AND” and “OR”. It is worth mentioning that the shape of a macrocut triangular membrane is exactly the same as the symbol of an electronic diode, and the conduction and cutoff directions of the ionic current are also exactly the same as those of electronic diodes. Our finding provides a facile and general strategy for fabricating a macroscale geometric asymmetry nanochannel-based two-dimensional lamellar membrane and shows the potential applications in complex highly integrated ionic circuits

Calcein-Modified Multinanochannels on PET Films for Calcium-Responsive Nanogating

Calcein-modified multiporous films with conical channels are introduced in a nanofluid device to enhance the calcium-responsive intensity and stability of ionic currents. Calcein with more carboxyls enhances the response of channels to calcium ions, and the capability of immobilized calcein for Ca²⁺-binding could be regulated by the deprotonation of these carboxyls

Photocontrollable Water Permeation on the Micro/Nanoscale Hierarchical Structured ZnO Mesh Films

Most research of responsive surfaces mainly focus on the wettability transition on different solid substrate surfaces, but the dynamic properties of the micro/nanostructure-enhanced responsive wettability on microscale pore arrays are lacking and still remain a challenge. Here we report the photocontrollable water permeation on micro/nanoscale hierarchical structured ZnO-coated stainless steel mesh films. Especially, for aligned ZnO nanorod array-coated stainless steel mesh film, the film shows good water permeability under irradiation, while it is impermeable to water after dark storage. A detailed investigation indicates that the special nanostructure and the appropriate size of the microscale mesh pores play a crucial role in the excellent controllability over water permeation. The excellent controllability of water permeation on this film is promising in various important applications such as filtration, microreactor, and micro/nano fluidic devices. This work may provide interesting insight into the design of novel functional devices that are relevant to surface wettability

Bio-inspired High-Performance Artificial Ion Pump Mediated by Subnanoscale Dehydration Hydration Effects

The energy conversion in plant chloroplast is carried out by pumping protons into the thylakoid for driving ATP synthesis. Inspired by ion active transport in living organisms, we attempted to design an artificial ion pump induced by subnanoconfinement effects. This ionic device uses two polarity functional nanoporous films as ion-selective valves at both ends and UiO-66 metal–organic framework-filled microchannels as ion storage cavities. In the charging process, ions could be pumped into the central cavities by nanovalves, which produced an ion gradient 10 to 100 times higher than the bulk, and were trapped within the subnanocages by dehydration. In the discharging process, the enriched ions were rehydrated and slowly released by the surface charge of the nanovalves, producing a sustainable ion current. The ion storage efficiency of this nanofluidic device could be improved to 60.3%, and the release time of ion current was also prolonged by 1 order of magnitude. This work combines the active and passive transport of ions to realize fast storage and slow release of ionic current, which provides an ion gradient-mediated novel energy conversion strategy

Improved Interfacial Ion Transport through Nanofluidic Hybrid Membranes Based on Covalent Organic Frameworks for Osmotic Energy Generation

Nanofluidic hybrid membranes integrated with asymmetrical surface charge, chemical composition, and geometric configuration exhibit unprecedented advantages in capturing the osmotic energy between river water and seawater. However, the output power is very restricted by the inefficient interfacial ion transport of the permselective membranes caused by the low-density pores and mismatch of the pore alignment. In this work, we developed a nanofluidic hybrid membrane constructed by ultrahigh pore-density covalent organic frameworks COF-LZU1 (Lan Zhou University-1) with the carbon nanotube/cellulose nanofiber (CNT-CNF) membrane. The COF-LZU1 layer possesses well-ordered and high-density pores, ensuring abundant selective ion transport. The CNT-CNF membrane functions as a robust support and also offers 3D charged space for the enhanced ion transport. The hybridization of the two layers dramatically increases the interfacial ion transport efficiency. Employing the COF-LZU1@CNT-CNF nanofluidic hybrid membrane to capture the osmotic energy stored between natural sea water and river water, a considerably high power density of 4.26 W m–2 is attained. This delicate design strategy offers ideas for the application of COF membranes in osmotic energy conversion

Solvent Fuming Dual-Responsive Switching of Both Wettability and Solid-State Luminescence in Silole Film

A multiresponsive switcher on both wettability and solid-state luminescence has great application potentials in novel smart devices. In this paper, a silole molecule of 1,2,3,4,5-hexaphenylsilole (HPS) was chosen to prepare thin films by spin-coating, and a solvent fuming dual-responsive switcher combining photoluminescent behavior and wettability was successfully achieved by changing the mode of solid-state molecular packing. This study suggests that HPS and other silole derivatives have a promising future for use in dual- and multifunctional switches in new technological applications

Dual High Adhesion Surface for Water in Air and for Oil Underwater

A new type of dual high surface adhesion both in an oil/water/solid system and in a water/air/solid system is reported. A walnutlike cuprous iodide (CuI) microcrystal surface, which is composed of numerous CuI nanocrystals, shows an amphiphobic, highly adhesive surface for water in air and for oil underwater. The maximum adhesive force is about 120.3 ± 1.6 μN in the air for a water droplet and about 23.8 ± 2.1 μN underwater for an oil droplet. These findings will help us to design novel high adhesive materials in two-phase or multiphase mediums