MXene‐Based Humidity‐Responsive Actuators: Preparation and Properties

Abstract

Water is a significant and abundant resource as well as a pure natural energy source. Many researchers have been reported on humidity-responsive actuators that mimick the humidity responsive behavior that widely exists in nature. Benefiting from advantages such as hydrophilicity, high electrical conductivity, and good dispersibility, MXenes (Ti 3 C 2 T x) show promising performance when applied to humidity-responsive actuators. This Minireview describes the preparation methods and structural characteristics of MXenes, and the mechanism of humidity responsive actuators. Recent important advances of MXene materials in actuators are objectively reviewed and evaluated, and existing issues are discussed. In addition, the development of these systems is outlined from the aspects of MXene preparation, structure control, design and assembly, and applications, and provides new ideas and guidance for the development of the next generation of high-performance MXene-based humidity-responsive actuators. 1 X n T x , where M is a transition metal (e. g. Ti, V, Nb, Mo, etc.), X is C or N element, and T represents chemical groups such as À OH, À O and À F. [31] Different from other two-dimensional materials, [a

Bioinspired humidity-responsive liquid crystalline materials: from adaptive soft actuators to visualized sensors and detectors

“…[14][15][16][17][18][19] Most efforts have been devoted to the preparation of humidity-driven actuators presenting various complex 3D motions such as bending, twisting and oscillating to convert humidity changes to mechanical output. 17,20,21 Liquid crystal (LC) materials are a class of emerging and appealing functional materials. In recent years, humidityresponsive LC materials such as LC polymers (LCPs), LC networks (LCNs) and cholesteric cellulose nanocrystals (CNCs) have been designed and prepared.…”

“…14–19 Most efforts have been devoted to the preparation of humidity-driven actuators presenting various complex 3D motions such as bending, twisting and oscillating to convert humidity changes to mechanical output. 17,20,21…”

Heterogeneity Regulation of Bilayer Polysaccharide Hydrogels for Integrating pH- and Humidity-Responsive Actuators and Sensors

“…Actuators are devices that are able to change the shape reversibly driven by external stimuli, , including light, − heat, − electricity, , humidity, − ions (such as salts , and pH , ), etc., or to release stored energy by mechanical deformation to realize programmed shape shifting or complete asynchronous/synchronous actions via the reconfiguration of geometry-determining skeletons and/or the programming of actuation-controlling units. − With the rapid development of actuators, the concept of ‘smaller, lighter, and softer’ becomes more and more important. As compared to the traditional actuators composed of hard and heavy substrates that are commonly driven by pneumatic, hydraulic, and electromagnetic technologies, soft actuators composed of compliant substrates allow for increased flexibility and adaptability for accomplishing sophisticated tasks with improved safety and device fabricating capability and as a result have attracted increasing interest in recent years.…”

Super-Fast Fabrication of MXene Film through a Combination of Ion Induced Gelation and Vacuum-Assisted Filtration

“…It is noteworthy that most of MXene flakes in MXene colloidal dispersion are individual and delaminated, under the effect of the vacuum pump, MXene flakes tightly deposit on the filter membrane surface face to face in a stretched manner, and freestanding MXene film with high intensity and outstanding conductivity can be obtained after drying. At present, MXene film fabricated through vacuumassisted filtration shows great potential for applications in fields such as electrochemical energy storage, [8][9][10] electromagnetic interference shielding, [11,12] smart materials [13][14][15][16] and other areas. [17,18] However, this technique has obvious processing limitations: requiring a large amount of time and energy, especially for thick MXene film.…”