Superhydrophobic cotton fabric membrane prepared by fluoropolymers and modified nano-SiO₂used for oil/water separation

Abstract

Cotton modified with polymer P(GMA-r-MMA)-g-PFPA and modified silica can obtain super-hydrophobic surfaces, and can be used as oil–water separation membrane for hexane, octane, kerosene, chloroform and water mixtures in batch and continuous operation.

Hydrophobic Modification of Spherical Y2O3:Eu3+ Powder Using Nonfluorinated Alkyl Silanes

“…The hydrophobic modification of Y 2 O 3 :Eu 3+ particles was performed using different nonfluorinated alkyl silanes (OTMS, DTMS, and ODTMS) with different alkyl chain lengths (C8, C12, and C18, respectively). The grafting of OTMS, DTMS, and ODTMS onto the surface of Y 2 O 3 :Eu 3+ nanospheres was performed at different pHs (3,5,7,9,11). The WCA of alkyl silanemodified Y 2 O 3 :Eu 3+ powders decreased in the order C18 > C12 > C8, and ODTMS generally gives the highest contact angle.…”

“…Moreover, its hydrophilic and oleophobic nature makes Y 2 O 3 :Eu 3+ unsuitable for use in fluorescent coatings. Hydrophobic modification is a viable solution to these problems, and can give Y 2 O 3 :Eu 3+ many excellent properties and functions, [7,8] such as self-cleaning ability, [9] anti-static performance, [10] oil/water separation functions, [11] and corrosion resistance. [12] The use of fluoride compounds such as poly (tetrafluoroethylene) (PTFE, Teflon) and perfluoroalkyl groups is a very common method for hydrophobic modification, [8] because fluorine atoms have a low surface free energy, which is due to their small diameter (42 pm) and higher electronegativity (3.98).…”

Fluorinated Polymer Brush-Grafted Silica Nanoparticles: Robust and Durable Self-Cleaning Coating Materials

“…There are reports where the core–shell morphology of fluorinated block copolymers plays an important role in increasing the surface roughness and hydrophobicity; even the presence of DA (Diels–Alder) linkages like anthracenyl, polyhedral oligomeric silsesquioxane maleimide, etc., in a self-healable fluoropolymer helps to increase the micro/nanosurface roughness. − Nevertheless, because of solubility issues, perfluoro- or semifluoro-based polymers limit their utility in these directions, rather known to be employed as host composite matrixes along with commercially available hydrophobic silica particles as nanofillers. In fact, most of the cases where hydrophobic silica particles were employed as a nanofiller, fluorine-based superhydrophobic surfaces were known to be achieved, making use of these nanofillers to impart multiscale roughness on the surface of the polyfluoro coating, and these coating fabrications are either dealt with a complex procedure or with issues like durability and robustness. − Moreover, any coating must be featured with long-term durability against organic solvent corrosion, mechanical wear, liquid flushing, etc., to be utilized in practical applications. , Hence, an easy and simple methodology of creating roughness to tune hydrophobicity in a robust and durable composite coating is of huge demand. Furthermore, unlike a conventional hydrophobic repellent surface (either repellent or wetting that follows the order of high to low surface tension for given liquids), it is quite challenging to create a surface having selective wettability and repellence to various liquids and holds promising demand in a wide range of practical applications in various fields.…”

Oil–Water Separation on Hydrophobic and Superhydrophobic Membranes Made of Stainless Steel Meshes with Fluoropolymer Coatings

“…The data presented in various works on the effect of WCA on the separation process are ambiguous and have a wide range of results. For example, Hou and Cao [41] obtained a separation efficiency of 98-99% on fluoropolymer-coated membranes with a WCA of 150 • ± 2 • , while Dong et al [42] obtained a stable separation efficiency of 95% on a membrane with a laser-structured copper surface with a WCA of 151 • ± 1 • . Yin [29] obtained a separation efficiency of over 99% and excellent stability even after 10 uses on a superhydrophobic-copper-hydroxide-coated membrane with a WCA of 154 • ± 2 • .…”