Table 1. Solubility of CPI Films with Different Diamines^a.

PI	Act	CHCl3	CH2Cl2	DMAc	DMF	DMSO	EtOH	MeOH	NMP	Py	THF	Tol
FDN PI	◎	◎	◎	◎	◎	◎	×	△	◎	◎	◎	○
FDN-OH PI	◎	×	△	◎	◎	◎	○	○	◎	◎	◎	×

^a◎: excellent, ○: good, △: poor, ×: very poor. Act: acetone, DMAc: N,N′-dimethylacetamide, DMF: N,N′-dimethylformamide, DMSO: dimethyl sulfoxide, EtOH: ethyl alcohol, MeOH: methyl alcohol, NMP: N′-methyl-2-pyrrolidone, Py: pyridine, THF: tetrahydrofuran, and Tol: toluene.