Flexible electrothermal polymer film based on reduced graphene oxide–water polyurethane

2020 ◽  
Vol 34 (25) ◽  
pp. 2050265 ◽  
Author(s):  
Ke Wang ◽  
Zhimin Zhou ◽  
Yuehui Wang

In this paper, waterborne polyurethane (WPU) conductive films incorporated with reduced graphene oxide (RGO) as conductive fillers were prepared by solution blending and tape casting method. The electrical conductivity, thermal conductivity and microstructures of the composite films were systematically investigated. The experimental results demonstrate that the electrical conductivity and thermal conductivity of the RGO–WPU composite films first increased then decreased with the increase of the RGO content. The resistivity of composite film with 7% RGO reaches to the smallest that is about [Formula: see text], and the thermal conductivity of the composite film with 7% graphene was about 0.29 W.m.K[Formula: see text], which an increase of 70% compared with pure WPU. The electrical conductivity of the composite film decreased with the increase of the original concentration of WPU solution and thickness of the composite film. As film heater, the composite film displayed effective and rapid heating at low input voltages owing to the good conductivity. With an input voltage was in the range of 10–24 V, the film took less than 30s to reach a steady-state temperature, demonstrating the fast response of the composite film heater and suitable for applications in the field of the fast temperature switching with low input voltages as flexible electrothermal heater.

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 317 ◽  
Author(s):  
Guang-jie Yuan ◽  
Jie-Fei Xie ◽  
Hao-Hao Li ◽  
Bo Shan ◽  
Xiao-Xin Zhang ◽  
...  

Thermally reduced graphene oxide/carbon nanotube (rGO/CNT) composite films were successfully prepared by a high-temperature annealing process. Their microstructure, thermal conductivity and mechanical properties were systematically studied at different annealing temperatures. As the annealing temperature increased, more oxygen-containing functional groups were removed from the composite film, and the percentage of graphene continuously increased. When the annealing temperature increased from 1100 to 1400 °C, the thermal conductivity of the composite film also continuously increased from 673.9 to 1052.1 W m−1 K−1. Additionally, the Young’s modulus was reduced by 63.6%, and the tensile strength was increased by 81.7%. In addition, the introduction of carbon nanotubes provided through-plane thermal conduction pathways for the composite films, which was beneficial for the improvement of their through-plane thermal conductivity. Furthermore, CNTs apparently improved the mechanical properties of rGO/CNT composite films. Compared with the rGO film, 1 wt% CNTs reduced the Young’s modulus by 93.3% and increased the tensile strength of the rGO/CNT composite film by 60.3%, which could greatly improve its flexibility. Therefore, the rGO/CNT composite films show great potential for application as thermal interface materials (TIMs) due to their high in-plane thermal conductivity and good mechanical properties.


2020 ◽  
Vol 8 (19) ◽  
pp. 9661-9669 ◽  
Author(s):  
Cong Huang ◽  
Qunli Tang ◽  
Qiushui Feng ◽  
Yanhua Li ◽  
Yali Xu ◽  
...  

An outer–inner dual space utilizing strategy is reported for the fabrication of an ultrahigh volumetric performance polydopamine-coated dopamine/reduced graphene oxide composite film.


2021 ◽  
Author(s):  
Yule Wu ◽  
Jun Rao ◽  
Feng Peng ◽  
Liping Zhang ◽  
Hui Gao ◽  
...  

Abstract Aquaternized hemicellulose (QH)/chitosan/reduced graphene oxide (rGO) composite film with good mechanical propertyand electrical conductivity was prepared bysolution-casting method. The effects of reduced graphene oxide contents on the structures and properties of the composite films were investigated.The mechanical property and electrical conductivity of the film with rGO containing 0.5 wt.% was reached 102.09 MPa and 12.8 × 10− 2 S/cm, respectively.Under the functions of hydrogen bonds and Van Der Waals forces, three components were combined to obtain QH/CS/rGO composite films with higher thermal stability and conductivity. Due to the compositing of rGO, the composite films showed good UV-blocking properties.This work provided a low-cost and sustainable pathway for the application of high-strength hemicellulose composite films with electrical conductivity and UV resistance in flexible electrode materials.


Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4247 ◽  
Author(s):  
Rita Petrucci ◽  
Isabella Chiarotto ◽  
Leonardo Mattiello ◽  
Daniele Passeri ◽  
Marco Rossi ◽  
...  

Natural methylxanthines, caffeine, theophylline and theobromine, are widespread biologically active alkaloids in human nutrition, found mainly in beverages (coffee, tea, cocoa, energy drinks, etc.). Their detection is thus of extreme importance, and many studies are devoted to this topic. During the last decade, graphene oxide (GO) and reduced graphene oxide (RGO) gained popularity as constituents of sensors (chemical, electrochemical and biosensors) for methylxanthines. The main advantages of GO and RGO with respect to graphene are the easiness and cheapness of synthesis, the notable higher solubility in polar solvents (water, among others), and the higher reactivity towards these targets (mainly due to – interactions); one of the main disadvantages is the lower electrical conductivity, especially when using them in electrochemical sensors. Nonetheless, their use in sensors is becoming more and more common, with the obtainment of very good results in terms of selectivity and sensitivity (up to 5.4 × 10−10 mol L−1 and 1.8 × 10−9 mol L−1 for caffeine and theophylline, respectively). Moreover, the ability of GO to protect DNA and RNA from enzymatic digestion renders it one of the best candidates for biosensors based on these nucleic acids. This is an up-to-date review of the use of GO and RGO in sensors.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Gen Liu ◽  
Wei Ma ◽  
Yan Luo ◽  
Deng-ming Sun ◽  
Shuang Shao

Poly(methylene blue) and electrochemically reduced graphene oxide composite film modified electrode (PMB-ERGO/GCE) was successfully fabricated by electropolymerization and was used for simultaneous determination of uric acid (UA) and xanthine (Xa). Based on the excellent electrocatalytic activity of PMB-ERGO/GCE, the electrochemical behaviors of UA and Xa were studied by cyclic voltammetry (CV) and square wave voltammetry (SWV). Two anodic sensitive peaks at 0.630 V (versus Ag/AgCl) for UA and 1.006 V (versus Ag/AgCl) for Xa were given by CV in pH 3.0 phosphate buffer. The calibration curves for UA and Xa were obtained in the range of 8.00 × 10−8~4.00 × 10−4 M and 1.00 × 10−7~4.00 × 10−4 M, respectively, by SWV. The detection limits for UA and Xa were3.00×10-8 M and5.00×10-8 M, respectively. Finally, the proposed method was applied to simultaneously determine UA and Xa in human urine with good selectivity and high sensitivity.


2021 ◽  
pp. 004051752199547
Author(s):  
Min Hou ◽  
Xinghua Hong ◽  
Yanjun Tang ◽  
Zimin Jin ◽  
Chengyan Zhu ◽  
...  

Functionalized knitted fabric, as a kind of flexible, wearable, and waterproof material capable of conductivity, sensitivity and outstanding hydrophobicity, is valuable for multi-field applications. Herein, the reduced graphene oxide (RGO)-coated knitted fabric (polyester/spandex blended) is prepared, which involves the use of graphite oxide (GO) by modified Hummers method and in-situ chemical reduction with hydrazine hydrate. The treated fabric exhibits a high electrical conductivity (202.09 S/cm) and an outstanding hydrophobicity (140°). The outstanding hydrophobicity is associated with the morphology of the fabric and fiber with reference to pseudo-infiltration. These properties can withstand repeated bending and washing without serious deterioration, maintaining good electrical conductivity (35.70 S/cm) and contact angle (119.39°) after eight standard washing cycles. The material, which has RGO architecture and continuous loop mesh structure, can find wide use in smart garment applications.


Author(s):  
Sara Maira Mohd Hizam ◽  
Nurul Izza Soaid ◽  
Mohamed Shuaib Mohamed Saheed ◽  
Norani Muti Mohamed ◽  
Chong Fai Kait

2019 ◽  
Vol 238 ◽  
pp. 54-57 ◽  
Author(s):  
Enliang Wang ◽  
Yanglong Wu ◽  
Md. Zahidul Islam ◽  
Yubing Dong ◽  
Yaofeng Zhu ◽  
...  

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