石墨烯/炭黑导电油墨的制备与性能研究

Preparation and characterization of graphene/carbon black conductive ink

采用改进Hummers法制备氧化石墨烯,并以维生素C为还原剂制备还原氧化石墨烯;然后以还原氧化石墨烯和炭黑为导电填料,以羧甲基纤维素钠为分散剂,乙醇、乙二醇、丙三醇和去离子水的混合溶液为溶剂,配制石墨烯/炭黑导电油墨。自制石墨烯/炭黑导电油墨导电笔,在相纸上直接书写线路,并对直写线路进行烧结处理。当烧结温度为100℃、烧结时间为30 min时,直写线路电阻值为0.06 MΩ。试验结果表明,石墨烯和炭黑颗粒连接致密,在烧结的墨层中能够形成导电通路。石墨烯/炭黑导电油墨直写线路具有良好的均匀性、附着力和导电性。以直写导电线路替代传统电路中的部分金属导线,可以成功组装纸基电路。该试验对实现导电油墨应用于喷墨印刷电路具有一定的参考价值。

The preparation of graphene/carbon black conductive ink and its direct writing on flexible paper substrates were studied in this paper. Firstly, the graphite oxide was prepared from natural graphite by using the modified Hummers＇ method. Secondly, the reduced graphene oxide suspensions were developed by using vitamin C as a reductant through chemical reduction. Finally, the graphene/carbon black conductive ink was fabricated with the obtained graphene and carbon black as conductive fillers, sodium carboxymethyl cellulose as binding agent and dispersant, and the mixture of ethyl alcohol, ethanediolglycol, glycerol and deionized water as solvent. The amount of graphene, carbon black, ethanol, ethylene glycol, glycerol and carboxymethylcellulose sodium were 96 mg, 504 mg, 12 mL, 30 mL, 30 mL, 480 mg and 51 mL, respectively. The conductive lines were directly written on flexible paper substrate by the self-manufactured conductive pen and were subsequently sintered. After then, the solvent in the conductive ink was volatilized, and the conductive fillers contacted with each other to form a uniform and dense conductive network, which can be seen in field emission scanning electron microscopy figures. The highest electrical conductivity of the graphene/carbon black conductive ink was obtained when the graphene/carbon black conductive ink was sintered for 30 min at 100℃, and the resistance value of the conductive line was only 0.06 MΩ. The escalating rate of the conductive-line resistance was in the range from 4.4% to 25.0%, which illustrated that the adhesion of the conductive lines was well. A part of metal wires in the traditional circuit conductive lines were made by directly writing. The paper-based circuit was composed of conductive wires, 3V power and light-emitting diode（LED）. The LED was illuminated when the circuit was closed, which indicated that graphene and carbon black particles contacted each other to form a conductive network. This experiment has reference value for the realization of the ink-jet-printed circuit by using conductive ink.