Molecular Design, Preparation, and Characterization of Fluoro-Containing Polyimide Ultrafine Fibrous Membranes with High Whiteness, High Thermal Stability, and Good Hydrophobicity

Abstract

Polymeric ultrafine fibrous membranes (UFMs) with high thermal stability and high whiteness are highly desired in modern optoelectronic applications. A series of fluoro-containing polyimide (FPI) UFMs with high whiteness, good thermal stability, and good hydrophobicity were prepared via a one-step electrospinning procedure from the organo-soluble FPI resins derived from a fluoro-containing dianhydride, 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), and various diamines containing either pendant trifluoromethyl (–CF3) groups or alicyclic units in the side chains. The obtained FPI UFMs, including FPI-1 from 6FDA and 3,5-diaminobenzotrifluoride (TFMDA), FPI-2 from 6FDA and 2′-trifluoromethyl-3,4′-oxydianiline (3FODA), FPI-3 from 6FDA and 1,4-bis[(4-amino-2-trifluoromethyl)phenoxy]benzene (6FAPB), FPI-4 from 4,4′-bis[(4-amino-2-trifluoromethyl)phenoxy]biphenyl (6FBAB), and FPI-5 from 6FDA and 4’-tert-butyl-cyclohexyl-3,5-diaminobenzoate (DABC) showed whiteness indices (WI) higher than 87.00 and optical reflectance values higher than 80% at the wavelength of 457 nm (R457), respectively. The FPI-5 UFM, especially, showed the highest WI of 92.88. Meanwhile, the prepared PI UFMs exhibited good hydrophobic features with water contact angles (WCA) higher than 105°. At last, the PI UFMs exhibited good thermal stability with glass transition temperatures (Tg) higher than 255 °C, and the 5% weight-loss temperatures (T5%) higher than 510 °C in nitrogen.

Preparation and Properties of Low-Dielectric Polyimide Films Containing Tert-Butyl

“…In particular, the PI-4 film exhibits a maximum hydrophobic angle of 80.16 • . The reason is that the large volume of the side chain in tert-butyl PI films reduces the interaction and packing density between molecular chains, which is conducive to improving the hydrophobicity of tert-butyl PI films [47]. Therefore, increasing the volume of anhydride of tert-butyl PI films contributes to reducing the adsorption of water.…”

Facile Fabrication of High‐White and Robust Superhydrophobic Ni/Al2O3 Composite Coating on Al Alloy

“…[32,33] Meanwhile, high-white material is widely used in transportation, weaving, and art. [34][35][36] Therefore, a firm superhydrophobic Al alloy with high-white surface can be prepared to satisfy the above requirements. This study presented a facile chemical bath method for fabricating robust Ni/Al 2 O 3 micronanostructures with appropriate roughness and high-whiteness on the Al alloy surface.…”