Facile fabrication of raspberry-like composite microspheres for the construction of superhydrophobic films and applications in highly efficient oil–water separation

Abstract

Inspired by the "lotus effect", we proposed a facile synthetic route toward raspberry-like PS@SiO 2 microspheres, which further lead to superhydrophobic surfaces. In this approach, monodispersed polystyrene (PS) microspheres were first synthesized via dispersion polymerization using polyvinylpyrrolidone (PVP) as stabilizer. The obtained PS microspheres were then used as template microspheres for biomimetic silification using tetraethyl orthosilicate (TEOS) as precursor. Upon adjusting the molecular weight of PVP and the concentration of NH 3 $H 2 O, the surface roughness of PS@SiO 2 microspheres can be well controlled. Furthermore, after hydrophobization treatment, by dropcasting the raspberry-like PS@SiO 2 microspheres onto a glass slide, dual-scale films were obtained, which had a similar surface morphology to that of the lotus leaf, exhibiting a water contact angle of 163.3 and water contact angle hysteresis of 4 . In addition, the oil-water separation ability of hydrophobic raspberry microsphere treated steel mesh was investigated. The results demonstrated excellent oil-water separation efficiency and reusability. This facile and robust synthesis technique for constructing a superhydrophobic surface hold great potential application in versatile and large-scale oilwater separation.

Wood protective coatings based on fluorocarbosilane

“…The combination of both methods of wood surface modification (deposition of silica nanoparticles followed by the impregnation with 5% solution of OFTES) resulted in a further decrease in water sorption by the FS1 sample to less than 20%. Both the reduction in water absorptivity and a significant increase of WCA observed for the FS1 sample are the result of synergistic interaction between silica nanoparticles and fluorosilane that leads to the formation of hierarchical raspberry-like structures on the surface of the discussed sample (Yu et al 2017). Similar or even slightly higher extent of water sorption reduction has been observed for the F2 sample coated with a solution comprising of 5% of OFTES and 22% of TEOS.…”

Controllable synthesis of silica nanoparticle size and packing efficiency onto PVP‐functionalized PMMA via a sol–gel method

“…However, relatively poor silica incorporation efficiency is a disadvantage in this manufacturing approach, limiting its commercial application. Thus, other approaches have been proposed, including the cationic azo‐initiator such as 2,2′‐azobis(2‐methyl propionamidine) dihydrochloride (AIBA), a comonomer such as acrylic acid, a coupling agent such as 3‐(trimethoxysilyl) propyl methacrylate (γ‐MPS), a stabilizer such as polyvinylpyrrolidone (PVP) . Schmid et al and Fielding et al reported an increase in the silica incorporation efficiency in the presence of AIBA.…”

“…In addition, silica nanoparticles require surface modification via hydrolysis such as γ‐MPS. To overcome these shortcomings, Yu et al and Zou et al proposed a method to prepare polymer/silica hybrid nanoparticles using PVP. PVP is an amphiphilic, hypotoxic, nonionic polymer widely used in scientific research and industry.…”

“…Zou et al reported the preparation of PVP‐functionalized‐polystyrene/silica hybrid nanoparticles that were independent of the initiator type and pH. Yu et al examined the adsorption behavior of silica particles with respect to molecular weight of PVP and catalyst amount of ammonium hydroxide. Although the effect of the synthesis of silica particles via a sol–gel method has been extensively reported, little research on the control of adsorbed silica particle size and the packing efficiency in PVP‐functionalized polymer/silica hybrid materials.…”

Effects of silica-based nanostructures with raspberry-like morphology and surfactant on the interfacial behavior of light, medium, and heavy crude oils at oil-aqueous interfaces

“…4). The roughness of the coating provided by the raspberry-like morphology particles is critical for the wetting properties of these SiO 2 nanofluid systems (Carcouet 2014;Carcouet et al 2014;Fan et al 2012;Yu et al 2017;Zanini et al 2017). The formation of these raspberry-like particles in brine-SiO 2 NP systems, with high surface area, may be attributed to the aggregation and self-assembly capabilities of SiO 2 NPs induced by the salt concentration (i.e., 5 wt% NaCl) (Uzelac et al 2017).…”