In this study, variation in the thermodynamic and kinetic properties of the casting solution achieved by tailoring initial composition (IC) of the polymer–solvent-nonsolvent ternary mixture is investigated to engineer pores in a polymer film prepared by liquid–liquid phase separation (LLPS). The driving force for liquid–liquid phase separation, identified as thermodynamic enhancement factor (T_E), is observed to influence the LLPS rate. At an IC closer to the phase boundary, the LLPS rate is higher. The kinetic restraint (K_R), which is dictated by the viscosity of the casting solution, also alters the LLPS rate. The interplay of these two opposing factors determines the final film morphology. The higher LLPS rate obtained from a larger T_E value leads to finger-like pore structure, while lowering LLPS rate by considering a casting solution with lower T_E results in polymer film with spherical sponge-like pores irrespective of casting solution viscosity. On the other hand, when the concentration of both the polymer and nonsolvent is high, i.e., for high K_R value, polymer film with interconnected pores and higher pore number density are obtained.

在这项研究中，研究了通过调整聚合物-溶剂-非溶剂三元混合物的初始组成 (IC) 来改变流延溶液的热力学和动力学特性，以在通过液-液相分离 (LLPS) 制备的聚合物薄膜中设计孔隙。 ）。观察到液-液相分离的驱动力，即热力学增强因子 ( T _E ) 会影响 LLPS 速率。在更接近相边界的 IC 处，LLPS 速率更高。由流延溶液的粘度决定的动力学约束 ( K _{R ) 也会改变 LLPS 速率。}这两个相反因素的相互作用决定了最终的薄膜形态。从更大的T获得的更高的 LLPS 速率_E值导致指状孔结构，而通过考虑具有较低T _E的浇铸溶液来降低 LLPS 速率会导致聚合物膜具有球形海绵状孔，而与浇铸溶液粘度无关。另一方面，当聚合物和非溶剂两者的浓度都高时，即对于高K _R值，获得具有连通孔和更高孔数密度的聚合物膜。