Reactivities of two polyimide (PI) monomer pairs, namely, pyromellitic dianhydride (PMDA, Kapton type tetracarboxylic dianhydride) and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFDB, fluorinated aromatic diamine) as well as 2,2-bis(3,4-anhydrodicarboxyphenyl)-hexafluoropropane (6FDA, fluorinated tetracarboxylic dianhydride) and 4,4'-diaminodiphenyl ether (ODA, Kapton type aromatic diamine) in forming polyamic acid (PAA, precursor of PI) were investigated in a mixture of supercritical carbon dioxide (scCO(2)) and 20 mol% N,N-dimethylformamide (DMF) by observing the phase changes occurred at 50 degrees C and 30 MPa. The results implicitly indicated that the growth rate of PAA of the PMDA-TFDB pair was lower than that of the 6FDA-ODA pair. Furthermore, the deposition of PI of the PMDA-TFDB pair onto microscale trenches was carried out in scCO2 containing 20 mol% DMF. The amount of PI (and PAA) of the PMDA-TFDB pair deposited inside the trenches increased with an increase in the monomer concentration and a decrease in the deposition temperature ranging from 100 to 250 degrees C. (C) 2017 Elsevier B.V. All rights reserved.