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Superhydrophobic and Low‐ k Polyimide Film with Porous Interior Structure and Hierarchical Surface Morphology
Author(s) -
Dong Fuping,
Li Hongwei,
Lu Liangyu,
Xiong Yuzhu,
Ha ChangSik
Publication year - 2019
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.201900252
Subject(s) - materials science , polyimide , morphology (biology) , contact angle , porosity , microelectronics , dielectric , composite material , relative humidity , chemical engineering , nanotechnology , layer (electronics) , engineering , thermodynamics , genetics , physics , optoelectronics , biology
Abstract Porous interior structured polyimide (PI) films with a hierarchical surface are fabricated from 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride and 4,4′‐oxydianiline by a water vapor induced phase separation process under a humid environment. Superhydrophobic properties with a water contact angle of 161° are obtained using the hierarchical surface morphology, which can be adjusted from flower‐like to wrinkle‐shape particles facilely by changing the relative humidity. The dielectric constant ( k ) of the PI film decreases sharply from 2.8 (film prepared under dry conditions) to ≈1.9 (film prepared under humid conditions) because of the interior porous structure and fluorine‐containing framework. Both a low‐ k and superhydrophobicity are very important parameters for PI films in microelectronic and insulating applications.