POLYIMIDE, POLYIMIDE-BASED POLYMER ELECTROLYTE MEMBRANE, MEMBRANE- ELECTRODE ASSEMBLY, AND POLYMER ELECTROLYTE FUEL CELL

The present invention provides a novel polyimide containing a diamine component having a fluorene skeleton and a novel polyimide-based polymer electrolyte membrane containing this polyimide as a main component and having properties based on this polyimide (for example, high resistance to methanol crossover). The polyimide of the present invention contains a structural unit (P) represented by the following formula (1). The polyimide-based polymer electrolyte membrane of the present invention contains the polyimide of the present invention as a main component.