Reduced Graphene Oxide/Carboxymethyl Cellulose Nanocomposites: Novel Conductive Films

2019 ◽  
Vol 19 (6) ◽  
pp. 3544-3550 ◽  
Author(s):  
Jutamas Ampaiwong ◽  
Pranee Rattanawaleedirojn ◽  
Kanokwan Saengkiettiyut ◽  
Nadnudda Rodthongkum ◽  
Pranut Potiyaraj ◽  
...  

Herein, carboxymethyl cellulose nanocomposite films incorporated with graphene oxide and reduced graphene oxide were successfully prepared by a novel approach for the first time, and their alternative properties compared with the original carboxymethyl cellulose films were disclosed. For carboxymethyl cellulose/reduced graphene oxide film preparation, sodium borohydride was used as a chemical reducing agent. The carboxymethyl cellulose films were prepared by using a solvent casting method, followed by an acid treatment to decrease the water solubility (98%) while enhancing the tensile strength (15%) and elastic modulus (32%) of the original carboxymethyl cellulose films. Overall, the addition of 1.0 wt% graphene oxide and reduced graphene oxide to the treated films increased the water solubility, water absorption, tensile properties and electrical conductivity. Particularly, the electrical conductivity was predominantly enhanced 1.3×105 times with graphene oxide and 2.2×105 times with reduced graphene oxide compared to the treated carboxymethyl cellulose film. The electrical conductivity of the treated carboxymethyl cellulose film also increased with an increase in reduced graphene oxide. The effects of reduced graphene oxide on the water solubility, water absorption, tensile properties and electrical conductivity of the treated carboxymethyl cellulose film were more pronounced than those of graphene oxide, especially for the electrical conductivity. In conclusion, graphene oxide and reduced graphene oxide might be alternative nanofillers for improving the carboxymethyl cellulose film properties. For the future applications, carboxymethyl cellulose/reduced graphene oxide films prepared by using this approach might be employed as alternative materials in electronic packagings and electrochemical biosensors.

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.


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

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3376 ◽  
Author(s):  
Nonjabulo P. D. Ngidi ◽  
Moses A. Ollengo ◽  
Vincent O. Nyamori

The greatest challenge in graphene-based material synthesis is achieving large surface area of high conductivity. Thus, tuning physico-electrochemical properties of these materials is of paramount importance. An even greater problem is to obtain a desired dopant configuration which allows control over device sensitivity and enhanced reproducibility. In this work, substitutional doping of graphene oxide (GO) with nitrogen atoms to induce lattice–structural modification of GO resulted in nitrogen-doped reduced graphene oxide (N-rGO). The effect of doping temperatures and various nitrogen precursors on the physicochemical, optical, and conductivity properties of N-rGO is hereby reported. This was achieved by thermal treating GO with different nitrogen precursors at various doping temperatures. The lowest doping temperature (600 °C) resulted in less thermally stable N-rGO, yet with higher porosity, while the highest doping temperature (800 °C) produced the opposite results. The choice of nitrogen precursors had a significant impact on the atomic percentage of nitrogen in N-rGO. Nitrogen-rich precursor, 4-nitro-ο-phenylenediamine, provided N-rGO with favorable physicochemical properties (larger surface area of 154.02 m2 g−1) with an enhanced electrical conductivity (0.133 S cm−1) property, making it more useful in energy storage devices. Thus, by adjusting the doping temperatures and nitrogen precursors, one can tailor various properties of N-rGO.


2019 ◽  
Vol 966 ◽  
pp. 386-391
Author(s):  
Eka Suarso ◽  
Anna Zakiyatul Laila ◽  
Firsta Agung Setyawan ◽  
Mochamad Zainuri ◽  
Zaenal Arifin ◽  
...  

In this study an investigation has been conducted on the effect of reduced graphene oxide (rGO) coating on increasing the value of Lithium Ferro Phosphate (LFP) electrical conductivity. This coating process uses a variation of the mass ratio of LiFePO4/rGO by 90%:10%, 70%:20%, and 67%:33%. The LiFePO4 precursor was prepared using the sol-gel rute from the main commercial materials, namely Li2CO3 powder as a source of lithium ions, FeCl2.4H2O as a source of iron and NH4H2PO4 powder as a phosphate source. As for the coating used rGO extracted from coconut shell waste. The samples were calcined with temperature variations of 600°C, 650°C and 700°C in an argon environment for 10 hour. The phase purity and crystal structure of LiFePO4 were analyzed using XRD. The analysis of data from XRD was done using the the Match!, Rietica, and MAUD software. Based on the results of XRD analysis, LiFePO4 with high purity and good crystallinity was obtained when the sample was calcined at temperature of 700°C. The results of the MAUD analysis show that the best size of LiFePO4 crystal is 86,54 nm. LiFePO4/rGO nanocomposite was successfully synthesized by mechanical ultracentrifugation method. The characterization of the value of electrical conductivity, carried out using a four-point probe. The results show that the greater the percentage of rGO, the higher the value of electrical conductivity. The mass ratio of 67% LiFePO4 and 33% rGO shows an increment in good conductivity values, from the original order of 10-8 S/cm to the order of 10-4 S/cm.


Nanoscale ◽  
2015 ◽  
Vol 7 (8) ◽  
pp. 3548-3557 ◽  
Author(s):  
Hao Wang ◽  
Shu-Guang Bi ◽  
Yun-Sheng Ye ◽  
Yang Xue ◽  
Xiao-Lin Xie ◽  
...  

Polymer-functionalized reduced graphene oxide (polymer-FG), produced as individually dispersed graphene sheets, offers new possibilities for the production of nanomaterials that are useful for a broad range of potential applications.


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