A Moisture‐Driven Actuator Based on Polydopamine‐Modified MXene/Bacterial Cellulose Nanofiber Composite Film

Abstract

As a new 2D material, MXene (Ti 3 C 2 T x ) shows great potential as a smart multifunctional humidity-responsive actuator due to its high hydrophilicity and conductivity but suffers from ambient oxidation and mechanical brittleness. Inspired by the mussels, the authors overcome these weaknesses by designing and fabricating a nacre-like and lamellar-structured composite film that consists of polydopamine-modified MXene and bacterial cellulose nanofibers, which shows improved properties as a moisture-driven actuator. The actuator has high conductivity (2848 S cm -1 ), excellent tensile strength (406 MPa), and toughness (15.3 MJ m -3 ). Moreover, the actuator is highly sensitive to moisture with the advantages of fast response (1.6 s), large deformation (176°), and high actuation force output (6.5 N m -2 ). It is additionally demonstrated that the actuator works as the electrical switch, robotic arm, and motor in a moisture-driven manner. Overall, it is believed that this work improves the drawbacks of current MXene-based actuators, laying the groundwork for their wider applications as moisture-driven devices.

High Energy and Power Density Peptidoglycan Muscles through Super‐Viscous Nanoconfined Water

“…Recent demonstrations and theoretical predictions showed that such WR actuation could be extremely powerful and efficient, [7][8][9] inspiring the growing studies and development of WR structures for actuators and artificial muscles. [10][11][12][13][14][15][16][17] Notable WR examples include a titanium oxide film [18] and a twisted carbon nanotube yarn, [19] which exhibit WR energy densities of ≈1250 and 1800 kJ m −3 (2.17 kJ kg −1 ), respectively. Microrobots equipped with WR actuators of 𝜋-stacked carbon nitride films [8] and polyethylene oxide nanofibers [20] have been demonstrated to exhibit autonomous locomotion powered by fluctuations in ambient RH.…”

“…Recent demonstrations and theoretical predictions showed that such WR actuation could be extremely powerful and efficient, [ 7 , 8 , 9 ] inspiring the growing studies and development of WR structures for actuators and artificial muscles. [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]…”

Gelation‐Assisted Assembly of Large‐Area, Highly Aligned, and Environmentally Stable MXene Films with an Excellent Trade‐Off between Mechanical and Electrical Properties

“…g) Comparison of the electrical conductivity and tensile strength between MAF‐0.25 and previously reported MXene‐based films. [ 14,16,23,25,27,28,31,35,38,44,48–53 ]…”

A high-performance humidity sensor based on alkalized MXenes and poly(dopamine) for touchless sensing and respiration monitoring

“…Hence, the excellent long-term stability of AMP3-based sensor was confirmed, which could be attributed to the tight bonding of the PDA layer with the surface of the AMX sheet and cut off the path of oxygen permeation. 35 The response and recovery times of the AMP3-based sensor were obtained by fastly moving the sensor from atmospheric environment (∼40% RH) into the humidity chamber (∼95% RH); the obtained values were 0.4 s and 0.5 s, respectively (see Fig. 2(e) and Fig.…”