碳纳米材料/刚性聚噻吩共混物和接枝物的溶液结晶行为研究

Rigid poly(3-alkylthiophene)(P3RT) is an important type of conductive polymers. There may exist synergetic effect between P3RT and carbon nano-materials, thus we proposed to study the solution crystallization of P3RT/carbon nano-material nanocomposites (including blends and grafting polymers) in this project. The effects of various internal factors (such as molecular weight, grafting density, length of the side group, type of carbon nano-material and aspect ratio) and external factors (including crystallization temperature and solvent) on the crystalline morphology, crystal orientation and stretching of carbon nanotubes (CNT) will be investigated. It is expected that the physical interaction and chemical grafting can be used to regulate the crystal orientation and morphology of P3RT on the surface of carbon nano-materials. We also utilize the interaction between P3RT and CNT to stretch CNT and thus obtain the macroscopically orientated crystals of P3RT/CNT nanocomposites. In order to propose the crystallization mechanism of rigid polymers on the surface of carbon nano-materials, we will study the chain conformation of P3RT on the surface of carbon nano-materials and the interaction between them using spectroscopic methods and computer simulation. Finally, the optoelectric property of the P3RT/carbon nano-material nanocomposites will be studied and correlated with the crystalline morphology. The results of this project will be helpful for improvement and design of optoelectric functional materials and will enrich the crystallization theory of polymers.

聚(3-烷基噻吩)(P3RT)是一类重要的导电高分子材料，它与碳纳米材料之间还可能存在协同效应，因此本项目研究P3RT/碳纳米材料复合体系(包括共混物和接枝物)的溶液结晶行为，考察各种内因(P3RT的侧链和分子量、接枝密度、碳纳米材料种类、长径比)和外因(结晶温度和溶剂)对复合物结晶形态(包括宏观形态、晶体取向、碳纳米管的拉伸)的影响。通过物理作用和化学接枝调控P3RT晶体在碳纳米材料表面的结晶形态和晶体取向，并利用P3RT与碳纳米管之间的相互作用将碳纳米管拉直，实现不同晶体的宏观取向。另外结合光谱和理论模拟的方法研究P3RT在碳纳米材料表面的构象和两者之间的作用力，从而提出刚性聚合物在碳纳米材料表面的结晶机理。还将研究P3RT/碳纳米材料复合物的光电性能，并关联其结晶形态。预期本项目的研究结果将对光电功能材料的性能改善和设计具有重要指导作用，并丰富聚合物结晶理论。

项目研究了具有平面共轭结构的聚合物聚(3-己基)噻吩(P3HT)、具有螺旋构象的共轭聚合物聚芴(PFO)和具有平面共轭结构的小分子化合物N,N-二辛基苝四羧基二酰亚胺(PTCDI-C8)在单壁碳纳米管(SWCNTs)存在下的溶液结晶行为。首次发现这三类共轭化合物都能够将SWCNTs拉直，其机理为刚性分子在溶液中通过-相互作用被吸附在SWCNTs表面，从而将其拉直。同时首次制备了小分子PTCDI-C8与SWCNTs形成的shish-kebab杂化纳米结构。另一方面，SWCNTs也可使被吸附的聚合物的共轭长度变长。作为比较，也研究了柔性高分子聚己内酯(PCL)与碳纳米管共混物和接枝聚合物的溶液和熔体结晶行为。研究发现PCL不能将单壁碳纳米管拉直，但可以在直径较大的多壁碳纳米管(MWCNTs)表面形成一层近由似平躺但具有不同取向的细小晶粒组成的晶体层，在该晶体层将MWCNTs包覆并将其拉直。同时，我们采用非常简便的基底倾斜方法，通过剪切诱导P3HT在汽-液-固界面结晶，制备了宏观取向的P3HT纳米线阵列；利用溶剂挥发诱导的水/空气界面自组装制备了大尺寸的聚(3-己基噻吩)-b-聚丙烯酸(P3HT-b-PAA)二维纳米带结构；以及采用水相法制备了P3HT嵌段共聚物/CdTe纳米晶杂化太阳能电池。总之，通过本项目的研究并建立了将SWCNTs拉直、以及简单制备宏观取向的P3HT纳米线阵列和大尺寸二维纳米带的方法，对共轭化合物及其碳纳米管复合物的应用有重要意义。另外，我们还研究了通过聚合物电纺纤维制备纳米纤维串晶的机理及具有广泛应用范围的双结晶过程的结晶动力学。