柔性显示用高阻隔聚酰亚胺的设计合成及其阻隔机理研究

Polyimides have attracted great interest recently due to their promising application in flexible organic light-emitting diodes (FOLED). However, traditional polyimides suffer from poor barrier performance when they are used as substrates, thus leading to short lifetime of FOLED. On the basis of this challenge, the main purpose of this project is to prepare new intrinsic type polyimide films with high barrier values and to study the corresponding barrier mechanism. Accordingly, a series of new diamine/dianhydride monomers with rigid and planar structures will be designed and synthesized by selecting appropriate synthetic methods and technique to prepare the new polyimides. Herein, rigid and planar structure units are employed to largely increase the rigidity and the packing density of polymer chains and to reduce the free volume of the resulting polymers to yield polyimide films with high barrier values. Furthermore, the relationship among the molecular structure, aggregation structure and the barrier performance will also be demonstrated through the systematic study on the effects of the rigid and planar moieties on the barrier and thermal properties. Meanwhile, based on theoretical calculation, it is expected to decipher the barrier mechanism of this new type of polyimide by the investigations of the free volume of the polymer and the diffusivity of gas molecules in the polymeric matrix. Consequently, from the achievements of the project, a new strategy for the design and synthesis of polyimides with high barrier values would probably be exploited, which will provide strong scientific basis for the development of ideal substrates for flexible solar cells and electronic devices.

针对传统聚酰亚胺应用于柔性有机电致发光器件(FOLED)衬底材料存在阻隔性能差，导致FOLED使用寿命短的问题，本项目致力于新型本征型高阻隔聚酰亚胺薄膜的制备及其阻隔机理的探讨。为此，拟设计合成一系列具有刚性平面结构的新型二胺/二酐单体，并选择合适的合成方法与工艺，制备系列新型聚酰亚胺材料。刚性平面结构单元可望有效提高聚合物分子链的堆砌密度和刚性，减小聚合物的自由体积，从而获得一类高阻隔聚酰亚胺薄膜材料。通过系统研究刚性平面结构单元对聚酰亚胺分子链结构、聚集态结构、阻隔性能以及热稳定性等参数的影响，阐明分子链结构、聚集态结构与阻隔性能之间的内在关联。结合分子模拟计算，从聚合物自由体积、分子链刚性以及气体分子对聚合物的溶解扩散性等角度揭示该类新型聚酰亚胺的阻隔机理。本项目的实施为合成高阻隔聚合物提供新的研究思路与方法，为柔性显示设备以及柔性太阳能电池、电子器件等衬底材料的发展提供科学依据。

针对传统聚酰亚胺应用于柔性有机电致发光器件(FOLED)衬底材料存在阻隔性能差，导致FOLED使用寿命短的问题，本项目致力于新型本征型高阻隔聚酰亚胺薄膜的制备及其阻隔机理的探讨。为此，结合分子模拟计算，以萘、咔唑、芴、芴酮等结构为中心，设计并合成了一系列具有刚性平面结构的新型二胺/二酐单体，采用两步法合成了新型聚酰亚胺，采用合适的工艺，制备了一系列新型聚酰亚胺薄膜。刚性平面结构单元有效提高了聚合物分子链的堆砌密度和刚性，减小聚合物的自由体积，从而获得了一类阻隔性能和热稳定性优异的聚酰亚胺薄膜材料。新型聚酰亚胺薄膜实现了水蒸气透过率和氧透过率分别低于10–3 g/m2•day 和10–3 cc/m2•day，玻璃化转变温度大于500 ℃，热膨胀系数小于3 ppm/K。通过分子模拟计算，获得了聚酰亚胺材料气体渗透相关的自由体积及分布、氢键、均方位移、内聚能密度、溶解度参数、扩散系数、扩散轨迹、吸附等温曲线（溶解系数）等参数。实验结合理论计算，系统研究刚性平面结构单元对聚酰亚胺分子链结构、聚集态结构、阻隔性能以及热稳定性等参数的影响，阐明了分子链结构、聚集态结构与阻隔性能之间的内在关联。从聚合物自由体积、分子链刚性以及气体分子对聚合物的溶解扩散性等角度揭示了该类新型聚酰亚胺的阻隔机理。在此基础上，制备了“双平面”结构的聚酰亚胺纳米复合材料。本项目的实施，提出了含刚性平面结构高阻隔聚酰亚胺制备的新思路与新方法，可为制备其它高阻隔聚合物提供新途径、实验依据和理论指导，为柔性显示设备以及柔性太阳能电池、电子器件等衬底材料的发展提供了科学依据。. 项目的实施，以本项目号为第一标注在高分子学科学术刊物上发表了SCI论文8篇；授权了有关具有刚性平面结构的新型二胺/二酐、高阻隔聚酰亚胺材料的发明专利8件；培养已毕业研究生3名，在读研究生2名，本科生十余名；作学术会议报告三次。