改質石墨烯/聚苯胺/聚苯乙烯磺酸複合材料之熱電性質研究

Abstract

本實驗主要分為兩個部份：(1) 改質奈米石墨烯(Graphene) (用對苯二胺(p-Phenylenediamine, p-PD)作改質劑)和製備石墨烯/聚苯胺/聚苯乙烯磺酸複合材料薄膜； (2) 探討這些複合材料薄膜的熱電相關特性，並探討改質石墨烯及未改質石墨烯所形成的複合材料的熱電性質及其差異。 第一部份利用對苯二胺(p-PD)氮原子上的孤對電子對石墨烯邊緣進行親核取代反應，並探討在不同溫度以及不同濃度下對苯二胺的改質情形，使用FTIR測出3200-3300cm-1處出現NH2基團之訊號，並且在極性溶劑中分散狀況也大幅改善，接著經由UV光譜、拉曼光譜、元素分析，我們證明其越高的溫度對於改質的成功率越低，然而在高溫時卻可以保留較多的sp2碳原子。在石墨烯和聚苯乙烯磺酸存在的溶液中，成功地使用原位聚合反應法聚合苯胺，成功地製備石墨烯/聚苯胺/聚苯乙烯磺酸複合材料薄膜，可以獨立成模。 第二部份的重點在熱電相關特性的研究。研究發現未改質石墨烯高分子複合材料的ZT值有0.97，而在改質石墨烯高分子複合材料最高的ZT值為1.07，此高分子複合材料會有負的Seebeck coefficient之值，同時我們使用SEM了解到在高分子才裡石墨烯分散情形並且證明在固含量5%時石墨烯的分散狀況是最好的，也由SEM看出改質石墨烯與未改質石墨烯高分子材料的差異。

This study is divided into two parts： (1) to modify Graphene with p-Phenylenediamine (p-PD) and to synthesize graphene/polyaniline/poly(styrene sulfonic acid) composite by in-situ polymerizatio； (2) to study the thermoelectric properties of modified(w/o) graphene/polyaniline/poly(styrene sulfonic acid) composites. The first part, nucleophilic substitution has happened on graphene sheet edge by using the lone-pair electrons which belongs to nitrogen atom of the p-PD and to discuss the modified situation in different temperature and different concentrations of p-Phenylenediamine. By FTIR analysis, a strong peak of amine group appeared between 3200 cm-1 to 3300 cm-1 wavenumber. The dispersion of modified-graphene in the polar solvent got better and better. By UV-Vis spectroscopy, Raman spectroscopy, XPS, We proof the higher temperature, and the lower success rate of the modified, but the more sp2 carbon in graphene sheet. The in-situ polymerization of aniline in the presence of graphene and poly(styrene sulfonic acid)(PSS) make the graphene/polyaniline(PAn)/PSS composits to be standing films. In the second part of thermoelectric characteristic study, we found that unmodified-graphene of polymer composites have ZT value is 0.97, however the modified-graphene of polymer composites which have the maximum ZT value 1.07. The Seebeck value of this polymer composites is negative. We understand graphene dispersion in polymer composites by using the SEM and proof the dispersion of graphene solid content in 5% is the best. By using the SEM, we find the difference of modified-graphene and unmodified-graphene of polyaniline: poly(styrene sulfonic acid)/graphene composite.