Electrothermal Actuator on Graphene Bilayer Film

Abstract

AC) stimuli. Xiao et al. [30] fabricated a graphene/poly(vinyldene fluoride) (PVDF) bilayer actuator by coating of PVDF solution onto a porous graphene paper. The hybrid film exhibited electrodriven vibration having rapid response rate, large displacement, and durable stability. In those electrothermal actuators, Joule heating was generated when electric current passed through the graphene film. Then the thermal expansion resulted in the large amount of deflection of the graphene/ polymer bilayer film. Polymer actuator is advantageous because of its high sensitivity, low energy input, and larger expansion rate. In this work, reduced graphene oxide (RGO)-based actuator was fabricated by spin-coating a reduced graphene oxide solution onto a polymer substrate obtaining a bilayer structure actuator. Poly dimethylsiloxane (PDMS) or polyethylene (PE) polymer substrate was used to support the electric-heated RGO layer and enlarge the thermal expansion deformation. [31] The bilayer film showed responsive bending motion under DC or AC voltage driving. Several actuate modes were proposed according to the bilayer structure design and driving current control. Experimental Section Preparation of RGOGraphite powder (2 g) was added into 46 mL of concentrated H 2 SO 4 , followed by adding 1 g NaNO 3 into above mixture under stirring and cooling in an ice bath condition. The mixture was continuous stirred while 6 g KMnO 4 was added slowly to keep the temperature of mixture below 5 °C. Then the mixture was kept at 35 °C for 30 min, followed by adding 90 mL deionized water while stirring, and the temperature would rise up to 95 °C. The mixture was kept stirring for a further 30 min, and 100 mL deionized water and 10 mL 30% H 2 O 2 were added in sequence. The oxidized material was then washed with 1:10 (v:v) HCl solution one time and deionized water three times to remove metal ions, followed by centrifugation. The collected product was dried in a vacuum drying oven at 45 °C.To obtain RGO, the as-synthesized GO powder (10 mg) was suspended in 20 mL of distilled water by ultrasonication until a yellowish-brown colloid was obtained. Subsequently, few drops of ammonia solution (35%) were added to increase the pH up to 8 allowing stability of the sheets. 15 µL hydrazine hydrate (0.1 m) solution was added to the above solution and refluxed at 98 °C for 100 min in a water bath, affording the formation Electrothermal Actuator Electrodriven bilayer actuator is designed and fabricated by spin-coating a reduced graphene oxide solution onto a polymer substrate. The bonded interface properties, electrical and thermal conductivities are characterized through scanning electron microscopy and X-ray diffraction. The bilayer actuator exhibits fast and large bending response when a direct current voltage is applied to the graphene layer. Whereas it exhibits oscillation when an alternating current voltage is applied to the bilayer actuator. The effects of the layer structure and the electro-operation methods on the bending motions are studied. Two new ...

Graphene‐Based Devices for Thermal Energy Conversion and Utilization

“…Based on the sG/PDMS bimorph actuator acting as a “finger,” a mechanical gripper was designed to realize the fast manipulation of the objects under a square wave voltage of 8 V, which opened up a broad prospect for the application of actuators in bionic field. Sang et al designed and fabricated an electrothermal bilayer actuator by spin‐coating a reduced graphene oxide solution onto a polymer substrate . The bilayer actuator exhibited a fast and large bending response with a direct current voltage applied on the graphene layer.…”

“…Third, choose proper elastic substrate materials with greater thermal expansion and excellent flexibility such as polyimide (PI), PDMS and so on. Among these polymers, PDMS has been widely used as the substrate in recent years in order to form larger coefficient of thermal expansion difference with the heating layer to increase the deformation further, such as the structure of SACNS/PDMS, sG/PDMS, CNT/PDMS, rGO/PDMS, PI/AgNW/PDMS, CNT(BP)/PDMS, and many others. In addition, studies have shown that decreasing the thickness of the actuator in an appropriate range can help achieving a shorter response time greatly due to the short heat transfer path as well as enlarging the deformation in a degree.…”

“…Sang et al designed and fabricated an electrothermal bilayer actuator by spin-coating a reduced graphene oxide solution onto a polymer substrate. [94] The bilayer actuator exhibited a fast and large bending response with a direct current voltage applied on the graphene layer. In order to broaden the application scope of electrodriven bilayer actuator, two new actuation modes of bending motion were put forward, namely, the structure design of actuator and driving current control.…”

Smart Devices Based on the Soft Actuator with Nafion-Polypropylene-PDMS/Graphite Multilayer Structure

“…In recent years, the demand for smart actuators based on flexible intelligent driving materials has increased [1][2][3][4]. The role of flexible intelligent driving materials is to convert external stimuli (such as light, heat, humidity, magnetic field/electric field) into executable actions or signals needed by processors through rapid, reversible and controllable structural/morphological changes [5][6][7][8][9][10][11][12][13][14][15][16]. Flexible smart actuators driven by these stimuli have significant advantages in the soft robot, electronic skin, bionic technology and other fields [17][18][19][20].…”

Laser Programmable Patterning of RGO/GO Janus Paper for Multiresponsive Actuators

“…Recently, GO has emerged as a versatile material for actuator design. For example, Liu and co‐workers prepared an electromechanical ring‐shaped actuator by combining an RGO layer with a PDMS layer, in which the RGO layer serves as an electric‐heated layer in the electrothermal actuator . Tang et al combined thermally expanding microspheres (TEMs) with RGO to fabricate an RGO–TEM–PDMS/PDMS bilayer actuator.…”