In a previous study, our group reported the fabrication of a series of colorless polyamide–imide (PAI) films (named TFDB-DABPO-TPC-6FDA) with good thermal stability. To further improve their properties, herein, the effect of adding blocks in molecules on the performance of polyimide (PI) films was studied. By changing the order and amount of the four reactants added each time, seven PAIs with different structures and block lengths were obtained. Their glass transition temperatures (T_g) ranged from 359 °C to 368 °C, and their transmittance at 430 nm (T₄₃₀) was 82.7%–85.1 %. Importantly, the coefficient of thermal expansion (CTE) of these seven PAIs decreased almost linearly from 31.1 to 18.5 ppm/K, making it possible to fabricate PI films with a desired CTE value for specific applications. Furthermore, the PAI-6-T film, which had the longest polyamide block and the best overall performance (T_g = 362 °C, CTE = 18.5 ppm/K, T₄₃₀ = 83.1 %, tensile strength = 179.4 MPa, dielectric constant (D_k) = 2.53, and dielectric loss (D_f) = 0.0088 at 10 GHz) was used as a substrate to fabricate a flexible printed circuit board (FPCB) and an organic light-emitting diode (OLED). Mechanical–electrical test shows that Ag was firmly bonded with the PAI-6-T film, and the resistance of FPCB@PAI-6-T only increased by 14.8 % after 150,000 folding tests. The flexible OLED@PAI-6-T exhibited pure green emission, a turn-on voltage of 3.0 V, a luminance of 1000 cd/m² at 6 V, a current efficiency of 1.31 cd/A, and an external quantum efficiency of 0.44 %.

在之前的研究中，我们小组报道了一系列具有良好热稳定性的无色聚酰胺酰亚胺（PAI）薄膜（名为TFDB-DABPO-TPC-6FDA）的制备。为了进一步改善其性能，本文研究了分子中添加嵌段对聚酰亚胺（PI）薄膜性能的影响。通过改变每次添加的四种反应物的顺序和用量，得到了七种不同结构和嵌段长度的PAI。它们的玻璃化转变温度（ T _g）范围为359°C至368°C，430 nm处的透光率（T ₄₃₀）为82.7%–85.1%。重要的是，这七种 PAI 的热膨胀系数(CTE) 从 31.1 几乎线性下降到 18.5 ppm/K，从而可以为特定应用制造具有所需 CTE 值的 PI 薄膜。此外，PAI-6-T薄膜具有最长的聚酰胺嵌段和最好的综合性能（ T _g  = 362 °C，CTE = 18.5 ppm/K，T ₄₃₀  = 83.1 %，拉伸强度= 179.4 MPa，介电常数）以( D _k ) = 2.53、介电损耗( D _f ) = 0.0088（10 GHz时）为基板来制造柔性印刷电路板（FPCB）和有机发光二极管（OLED）。机电测试表明Ag与PAI-6-T薄膜牢固结合，FPCB@PAI-6-T经过15万次折叠测试后电阻仅增加14.8%。柔性OLED@PAI-6-T表现出纯绿光发射，开启电压为3.0 V，6 V下亮度为1000 cd/m ²，电流效率为1.31 cd/A，外量子效率为0.44%。