A series of biobased polyimides bearing a structure derived from a predetermined tetracarboxylic dianhydride was synthesized. By ionizing the COOH group of the side chain with potassium hydroxide, four kinds of polyimides were solubilized in water, and the water-soluble polyimides were cast onto films over an aqueous solution, leading to higher optical transparency than that of non-water-soluble polyimides. ¹H nuclear magnetic resonance measurements of the polyimides revealed no residual reactants from the polymerization process or side-chain modification. Partial crosslinking of the water-soluble polyimide chains by condensation of the carboxylate side chain with an amino acid-based diamine such as 4-aminophenylalanine or 4,4′-diamino-α-truxillic acid induced the formation of polyimide hydrogels. The remaining COOK groups of the obtained hydrogel were protonated/deprotonated by changing the pH, accompanied by reversible shrinking and swelling.

合成了一系列具有衍生自预定四羧酸二酐的结构的生物基聚酰亚胺。通过用氢氧化钾电离侧链的COOH基团，四种聚酰亚胺溶于水，水溶性聚酰亚胺在水溶液上流延成薄膜，比非水溶性聚酰亚胺具有更高的光学透明度聚酰亚胺。聚酰亚胺的¹ H 核磁共振测量显示没有来自聚合过程或侧链改性的残留反应物。通过羧酸盐侧链与基于氨基酸的二胺（例如 4-氨基苯丙氨酸或 4,4'-二氨基-α）缩合使水溶性聚酰亚胺链部分交联-truxillic acid 诱导聚酰亚胺水凝胶的形成。所得水凝胶的剩余 COOK 基团通过改变 pH 值进行质子化/去质子化，并伴随可逆的收缩和溶胀。