Flexible polyimide (PI) films with simultaneously excellent dimensional stability and toughness were vital for the application and reliability of flexible display. Thus, in this paper, we designed a novel PI film containing point-to-face multi-coordination structure. The coordination structure was constructed by introducing Cu²⁺ and benzimidazole ligands into polyimides, and the existence of the point-to-face multi-coordination was proved. Excellent toughness and dimensional stability under high temperature, multiple heating-cooling cycles, and cyclic tension of PI films were realized, resulting from destruction and rapid reconstruction of point-to-face multi-coordination structure with the advantage of large bonded areas. Compared with PI without Cu²⁺ (PICu0), the thermal expansion coefficient of PI with 20mol% Cu²⁺ (PICu20) reduced 94%, and the tensile strength, percentage of breaking elongation and fracture energy of PICu20 increased by 40%, 45% and 174%, respectively. Furthermore, the water absorption of PICu films dropped and the dielectric breakdown strength was maintained.

同时具有出色的尺寸稳定性和韧性的柔性聚酰亚胺（PI）膜对于柔性显示器的应用和可靠性至关重要。因此，在本文中，我们设计了一种新颖的包含点对面多配位结构的PI膜。通过将Cu ²⁺和苯并咪唑配体引入聚酰亚胺中来构建配位结构，并证明了点对面多配位的存在。通过破坏和快速重建具有较大结合面积的点对面多配位结构，实现了PI膜在高温下具有优异的韧性和尺寸稳定性，多次加热-冷却循环以及PI膜的循环张力。与不含Cu ^2+的PI相比（PICu0），含有20mol％Cu ²⁺的PI（PICu20）的热膨胀系数降低了94％，PICu20的拉伸强度，断裂伸长率和断裂能分别增加了40％，45％和174％。此外，PICu膜的吸水率下降并且保持了介电击穿强度。