Polyaniline/Reduced Graphene Oxide/Carbon Nanotube Composites for Actuation-Based Sensing for Energy Storage

Abstract

Until now, many carbon-based soft actuators with excellent performance have been developed, and various indicators of actuators are close to the limit. However, compared with the intelligence and versatility of natural biological muscles, soft actuators still have the shortcomings of single function and insufficient intelligence. Herein, polyaniline/reduced graphene oxide/carbon nanotube (PANI/RGO/CNT) composites are fully used to design and fabricate a smart gripper with a self-powered temperature-sensing function. First of all, the PANI/RGO/CNT composites have the characteristics of low coefficient of thermal expansion (CTE) and negative temperature resistivity. By cooperating with polymers with high CTE, a multifunctional bilayer actuator with a temperature-sensing function can be constructed with a temperature coefficient of resistance of 2364 ppm K–1. With the light irradiation (power density of 300 mW cm–2), the surface temperature, bending curvature, and resistance change of the actuator are as high as 48.8 °C, 0.86 cm–1, and −6.1%, respectively. Second, the PANI/RGO/CNT composite also possesses the advantage of large-area capacitance (165.8 mF cm–2). Thus, an integrated bilayer actuator with energy storage modules can be constructed through clever structural design and used as deformable supercapacitors. Finally, based on the similarity in structure and actuation mechanism of the multifunctional bilayer actuator and the integrated bilayer actuator, a smart gripper with a self-powered temperature-sensing function is proposed to provide real-time feedback of the change in temperature of the smart gripper as it grasps the object. The versatility of the smart gripper is achieved without increasing the complexity of the structure, demonstrating the advantages of the design concept of integrating sensing and energy storage in the design of soft actuators. The proposed PANI/RGO/CNT composites have great potential to be used in the fields of intelligent actuators, deformable supercapacitors, and artificial muscles.

Soft multi‐layer actuators integrated with the functions of electrical energy harvest and storage

“…Thus, in addition to the above-mentioned actuators with integrated energy generation functions, the actuators integrated with energy storage functions have also developed rapidly. [43,44,[65][66][67][68] For example, soft supercapacitors are widely used in the field of actuators integrated with energy storage functions due to their flexible structure. [33,44,65] Typically, carbonbased materials (such as graphene, CNTs, and their derivatives) with high surface area, high electrical conductivity, light absorption ability, and thermal conductivity have been widely reported for both actuators and supercapacitors.…”

“…For example, Weng et al presented a PANI/RGO/CNT smart gripper with self-powered temperature sensor. [67] As depicted in Figure 6a (I-II), the smart gripper comprises a multi-function actuator that integrates a temperature sensing function (with a temperature coefficient of resistance of 2364 ppm K À 1 ) and an integrated actuator that combines an energy storage function. The smart gripper can shut, grab, and transfer an item to the right under NIR light, as shown in Figure 6a (III).…”

“…Among them, multi‐functional, soft, and integrated actuators which integrate energy storage functions in soft actuators and miniaturize their volume are much needed. Thus, in addition to the above‐mentioned actuators with integrated energy generation functions, the actuators integrated with energy storage functions have also developed rapidly [43,44,65–68] . For example, soft supercapacitors are widely used in the field of actuators integrated with energy storage functions due to their flexible structure [33,44, 65] .…”

Multifunctional Actuator Based on Graphene/PDMS Composite Materials with Shape Programmable Configuration and High Photothermal Conversion Capability

“…The main materials used in the development of intelligent soft robots include hydrogels, 29,30 shape memory polymers, 20,31 two-dimensional transition metal carbides/nitrides (Mxenes), 32−35 and carbon materials (graphene 36−38 and its derivatives, 39−41 carbon nanotubes, 42,43 etc.). Among them, carbon materials have excellent light absorption and photothermal conversion capabilities.…”

“…The main materials used in the development of intelligent soft robots include hydrogels, , shape memory polymers, , two-dimensional transition metal carbides/nitrides (Mxenes), − and carbon materials (graphene − and its derivatives, − carbon nanotubes, , etc.). Among them, carbon materials have excellent light absorption and photothermal conversion capabilities. , Wang et al fabricated a three-layered composite soft robot composed of carbon nanotubes, polydimethylsiloxane (PDMS), and polyvinylidene fluoride (PVDF), which can rapidly respond to liquid, vapor, and light stimuli.…”