Thermodynamics and kinetics of polyoxyethylene alkyl ether evaporation from inkjet-printed carbon nanotube thin films by vacuum annealing
Thermodynamics and kinetics of polyoxyethylene alkyl ether evaporation from inkjet-printed carbon nanotube thin films by vacuum annealing
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真空退火喷墨印刷碳纳米管薄膜聚氧乙烯烷基醚蒸发的热力学和动力学
DOI：
10.1088/2058-8585/aac349
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
and Kenji Ishida
中科院分区：
文献类型：
--
作者：
Shohei Horike;Tatsuya Fukushima;Takeshi Saito;Yasuko Koshiba;Masahiro Morimoto;Masahiro Misaki;and Kenji Ishida
将通过超声处理与表面活性剂分散在水中的碳纳米管（CNT）用作印刷油墨。然而，表面活性剂通常是电绝缘体，保留在制备的CNT膜上，降低其导电性。虽然通过退火的蒸发是一种有效的去除工艺，但它通常在高温（180 ℃）下在空气中进行，使其不适用于在普通塑料基板上印刷。这项工作演示了蒸发表面活性剂的真空退火过程。聚（氧杂环丁烷）4月桂基醚（Brij L4）-一种非离子表面活性剂-使用。通过热重分析和红外光谱分析了其蒸发行为（热力学和动力学）。TG测量证实真空下的蒸发起始温度（51.0 ℃）低于空气中的蒸发起始温度（148.7 ℃）。IR结果表明，通过在130 ℃下真空退火，除去了100%的Brij L4。从活化能结果计算出表面活性剂从CNT的脱附能约为10 kJ mol− 1;该值比其他表面活性剂报告的值小约半到一个数量级。该能量将允许表面活性剂的充分的吸附相互作用以稳定地分散纳米管，但是该能量足够小以允许通过热处理容易地去除表面活性剂。真空退火后的碳纳米管薄膜的电阻值比空气中退火后的碳纳米管薄膜的电阻值显著降低。因此，该工艺可用于制造具有碳纳米管的柔性印刷电子器件。
Carbon nanotubes (CNTs) dispersed in water by sonication with surfactants are used as printing inks. However, surfactants are usually electrical insulators that remain on the prepared CNT films, reducing their conductivity. While evaporation by annealing is an effective removal process, it is usually performed at high temperatures (180 C) in air, making it inapplicable for printing on common plastic substrates. This work demonstrates a vacuum annealing process for evaporating surfactants. Poly (oxyethylene) 4 lauryl ether (Brij L4)—a nonionic surfactant—was utilized. Its evaporation behaviors (thermodynamics and kinetics) were analyzed by thermogravimetric (TG) analysis and infrared (IR) spectroscopy. The TG measurements confirmed that the evaporation onset temperature under vacuum (51.0 C) was lower than that in air (148.7 C). The IR results revealed that∼ 100% Brij L4 was removed by annealing under vacuum at 130 C. The desorption energy of the surfactant from CNTs was calculated from the activation energy results to be about 10 kJ mol− 1; this value is about a half to one order of magnitude smaller than those reported for other surfactants. This energy would allow adequate adsorption interactions for the surfactant to stably disperse the nanotubes, but is sufficiently small to allow easy removal of the surfactant by thermal treatment. The electrical resistance of the vacuum-annealed CNT thin film dramatically decreased compared with that of the film annealed in air. Therefore, this process can be used for fabricating flexible printed electronics with CNTs.