Unveiling Aqueous Polymerization of Poly(amic acid) Salts for Eco-Friendly and Robust Aromatic Polyimide Structuring

The development of water-borne poly(amic acid) salts (W-PAAS) for aromatic polyimide (PI) synthesis represents a significant advancement, offering a straightforward and environmentally friendly process. This study provides an in-depth investigation into the intricate reaction mechanisms of W-PAAS polymerization in an aqueous medium facilitated by an organic base. The polymerization primarily occurs at the interface of dianhydride particles with water, highlighting the critical role of this interface in the reaction. The presence of the organic base lowers the energy barrier, enabling the formation of high-molecular-weight polymer chains. The resulting PI films derived from W-PAAS aqueous solutions exhibit properties comparable to those of traditional organic-solvent-based and commercial PI films. Additionally, the W-PAAS solution can be easily transformed into a hydrogel, highlighting its potential for three-dimensional (3D) structuring applications. This research introduces a novel platform for rational molecular design within aqueous synthetic systems, broadening the scope of high-performance material applications while promoting environmental sustainability.