Fluorine-free superhydrophobic meshes decorated with porous microspheres for highly efficient oil-water separation

In this study, we report a new facile method to prepare fluorine-free superhydrophobic separation films by deposition of micron-sized hydrophobic polyhigh internal phase emulsion (polyHIPE) microspheres on stainless steel meshes. The so-called polyHIPE microspheres are polymer ones with interconnected porous structures, which are prepared by gamma-ray radiation polymerization of (W/O HIPE)/W double emulsions stabilized by a single emulsifier 12-acryloyloxy-9-octadecenoic acid using a one-step emulsification in this work. The oil-water separation results show that our self-made hydrophobic meshes have excellent oil-water separation efficiency (about 99.5%), outstanding permeation flux (no less than 187.5 L/[m(2)center dot min] and the maximum value of 1850 L/[m(2)center dot min]). The oil flux of common organic solvents, water contact angle and water intrusion pressure of these hydrophobic meshes can be readily tuned by changing the size, amount and composition of polyHIPE microspheres. It is worth noting that the superhydrophobic meshes remain excellent separation efficiency and stability after 10 cycles in corrosive environments. More importantly, these superhydrophobic meshes can also efficiently separate surfactant-stabilized water-in-oil emulsions. The polyHIPE microspheres decorated superhydrophobic meshes that can easily realize large-scale production have potentially practical applications in sewage treatment or separation/purification.