Multistimulus Responsive Actuator with GO and Carbon Nanotube/PDMS Bilayer Structure for Flexible and Smart Devices

Abstract

Smart devices with abilities of perceiving, processing, and responding are attracting more and more attentions due to the emerging development of artificial intelligent systems, especially in biomimetic and intelligent robotics fields. Designing a smart actuator with high flexibility and multistimulation responsive behaviors to simulate the movement of creatures, such as weight lifting, heavy objects carrying via simple materials, and structural design is highly demanded for the development of intelligent systems. Herein, a soft actuator that can produce reversible deformations under the control of light, thermal, and humidity is fabricated by combining high photothermal properties of CNT/PDMS layer with the natural hydrophilic GO layer. Due to the asymmetric double-layer structure, the novel bilayer membrane-based actuator showed different bending directions under photothermal and humidity stimulations, resulting in bidirectional controllable bending behaviors. In addition, the actuation behaviors can be well controlled by directionally aligning the graphene oxide onto carbon nanotube/PDMS layer. The actuator can be fabricated into a series of complex biomimetic devices, such as, simulated biomimetic fingers, smart "tweezers", humidity control switches, which has great potential applications in flexible robots, artificial muscles, and optical control medical devices.

Recent Advances in Photoactuators and Their Applications in Intelligent Bionic Movements

“…These photothermal actuators are generally composed of a bilayered structure with light absorption ability: a passive layer with a small coefficient of thermal expansion (CTE) and a thermal expansion layer with a large CTE. Carbon-based materials such as carbon black, [54] carbon nanotube (CNT), [28,55] graphite, [56] graphene oxide (GO), [57][58][59] and MXene [60][61][62] are often used as light absorption layers. Polymers having large CTE such as poly(dimethylsiloxane) (PDMS), [48] polyimide (PI), [63] polycarbonate (PC), [49] biaxially oriented polypropylene (BOPP), [64] poly(vinylidene fluoride) (PVDF), [65] polyethylene (PE) [66] serve as thermal expansion layers.…”

“…Owing to the advances in natural smart systems, numerous responsive materials that can transform dynamic and reversible shape deformations into locomotions have emerged under various external stimuli such as light, [1][2][3][4][5] humidity, [6][7][8][9][10][11][12] electric field, [13][14][15][16][17][18] organic solvents, [19][20][21] heat, [22] magnetism, [23][24][25] or a combination of multiple types of stimuli thereof. [26][27][28][29][30][31][32][33][34] Such materials exhibit the potential for applications in soft robotics, artificial muscles, and smart devices. [35][36][37][38][39] Considerable efforts have been made in the development of high-performance, multi-functional actuators with regard to material selection, materials and photochemical actuators are generated through reversible actuation by photoisomerization and photodimerization.…”

Advances in Stimuli-Responsive Soft Robots with Integrated Hybrid Materials

“…The light is untethered and can be controlled from an exterior side of the systems. Along with this optical advantage, photo-to-thermal responsive multi-functional soft robots have been extensively developed [41,[65][66][67][68][69][70][71][72][73]. For example, Cheng et al developed a rectangular-shaped graphene oxide (GO) film walker in response to an infrared (IR) light on/off process ( Figure 5C) [65].…”

Flexible Actuators for Soft Robotics

“…These studies have laid an important foundation for the application of optical actuators in the intelligent soft robotic field. Moreover, scientists have combined the unique features of the aforementioned types of the stimulations (e.g., light, humidity, and electricity) and designed multistimuli–responsive flexible actuators, further enhancing the performance and enriching the application range of flexible actuators on humans . For soft robotic systems on nonhumans, electrical actuators and pneumatic actuators have been widely investigated by researchers.…”