Free-standing, flexible, multifunctional, and environmentally stable superhydrophobic composite film made of self-assembled organic micro/super-nanostructures through solution process

A free-standing, flexible, transparent, and fluorescent superhydrophobic composite film is fabricated by drop-casting a layer of organic self-assembled flowerlike micro/super-nanostructures on top of a hydrophobic polyimide film. The solution process to grow the organic super-nanostructures, fabricate the composite film, and lift-off the film from the mother substrate, ensures the process simplicity, low-cost, and scalability. The water contact angle (CA) of the superhydrophobic composite films reaches as high as 159.6 degrees, and the sliding angle (SA) is less than 2 degrees without any further low surface energy treatment. The as-prepared film shows superhydrophobicity with a CA above 150 degrees covering the entire pH range. Moreover, the composite film exhibits good environmental stability against both organic solvent treatment and being exposed to acidic and aqueous solutions. The fluorescence from the composite film extends the potential application of the film into the optoelectronic field. The results may open up an avenue to prepare smart and intelligent superhydrophobic films for application. (C) 2014 Elsevier Inc. All rights reserved.