Formation of deformed honeycomb-patterned films from fluorinated polyimide

Fabrication of honeycomb-patterned films from one of the soluble fluoro-polyimides in a humid atmosphere was reported in this paper. This polyimide was synthesized from 2,2′-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and 4,4′-methylene dianiline (MDA) by two-step method. The obtained polyimide kept excellent rigidity and thermal stability, and especially, exhibited good solubility both in strong bipolar solvents and in common organic solvents. By blowing airflow across the surface of the deposited solution horizontally, the pores locating at the windward side of the film could change their morphologies from circle to ellipse, while the pores at the leeward side were almost kept their shapes. A detailed research about the pore deformation on various regions in a same film was carried out. At last, the differences in pattern formation between dynamic and static environment were tested, and the results showed that pores fabricated under flowing atmosphere were smaller and more regular than those formed under static condition.