A Magnetic Gated Nanofluidic Based on the Integration of a Superhydrophilic Nanochannels and a Reconfigurable Ferrofluid

Abstract

gating as a promising candidate has been proposed as it is an easy manipulation and high stability method. [7] However, how to regulate the ion transport in nanoscale with excellent controllability, good stability, and high gating ratio remains a challenge.Ferrofluid as an intelligent liquid, which could reconfigure the surface topography under the magnetic field, could be used as a smart liquid gating to control the ion transport in nanoscale. Herein, we designed a magnetic gated nanofluidic (MGN) based on the integration of superhydrophilic nanochannels and reconfigurable ferrofluid. The reconfigurable shape of the ferrofluid, resembling the biological counterparts of the sebum membrane of the epidermis, is used to control the ion transport. As shown in Figure 1a,b, through manipulating the permanent magnet to change the steric configuration of the ferrofluid, [8] we constructed a switchable gating system with high gating ratio (≈10 000) and excellent stability (130 cycles). And the shapeable ferrofluid not only regulates the ion flow similar to the sebum membrane in immune systems but also realizes fast response to the magnetic field. The experiment and simulation analysis prove that the superhydrophilic surface with bound water is vital to our system, [9] which prevents the ferrofluid from entering the nanochannel of the membrane, and leads to a low oil adhesion further facilitating the high The design of intelligent gating in nanoscale is the subject of intense research motivated by a broad potential impact on science and technology. However, the existing designs require complex modification and are unstable, which restrict their practical applications. Here, a magnetic gated nanofluidic is reported based on the integration of superhydrophilic membranes and reconfigurable ferrofluid, which realizes the gating of the nanochannel by adjusting the steric configuration of the ferrofluid. This system could achieve ultrahigh gating ratio up to 10 000 and excellent stability up to 130 cycles without attenuation. Experiments and theoretical calculations demonstrate that the switch is controlled by the synergy of magnetic force and the interfacial tension. The introduction of ferrofluid and superhydrophilic nanochannels in this work presents an important paradigm for the nanofluidic systems and opens a new and promising avenue to various developments in the fields of materials science, which may be utilized in medical devices, nanoscale synthesis, and environmental analysis. FerrofluidsRegulating substances transport such as ion and water in nanoscale is of great significance in real-world applications, such as biological sensing, [1] drug delivery, [2] species separation, [3] energy harvesting, [4] etc. So far, various functional membranes for ion gating have been widely investigated with external triggers ranging from a single response to multiple responses. [5] Although those gating systems are intelligent and efficient, their applications are plagued with the problem of low stability, slow response, comple...

Rational ion transport management mediated through membrane structures

“…In addition, magnetic-responsive nanochannels were obtained through the combination of superhydrophilic AAO and a magnetically controlled ferrofluid, which showed a high gating ratio of 10,000 owing to the synergistic effect of both the magnetic force and the interfacial tension (Figure 14G). [247] Mechanosensitive nanochannels have also attracted the attention of researchers, including CNTs, [248,249] graphene crown ethers, [250,251] and single-layer MoS 2 with sub-nanometer pores. [252] Most recently, Hou et al reported a dynamic nanochannel system composed of CNTs embedded in PDMS (Figure 14H).…”

“…Reproduced with permission. [ 247 ] Copyright 2018, Wiley‐VCH. (H) Curved CNTs (left) and various ion transport behaviors (right).…”

Light‐Controlled Ionic/Molecular Transport through Solid‐State Nanopores and Nanochannels

“…With the rapid development of nanotechnology, various functional solid-state nanofluidic devices responding to diverse external stimuli including physical and chemical ones such as light, [65][66][67] temperature, [68,69] voltage, [70,71] magnetism, [72] pH, [73,74] ions [75] and molecules, [76] have been fabricated with different kinds of materials to selectively regulate mass transport. [14] In particular, the photo-responsive solid-state nanopores/nanochannels have attracted a wide range of attention from multidisciplinary fields due to their unique superiority over other external stimuli.…”

Switchable smart porous surface for controllable liquid transportation

“…[27][28][29][30][31][32][33] Moreover, based on a morphology change from spherical to disc shape, the magnetic liquid can be used as a cover to achieve controllable ion transportation on an anodic alumina oxide membrane within a limited surface area. 34 This research provides a valuable paradigm for ion transportation at the nanoscale. So far, the modulation of surface wettability and directional transportation based on a tunable magnetic liquid composite surface has been extensively studied.…”