Inherently Superoleophobic Nanocomposite Coatings by Spray Atomization

Abstract

We describe a technique to fabricate, for the first time, superoleophobic coatings by spray casting nanoparticle-polymer suspensions. The method involves the use of ZnO nanoparticles blended with a waterborne perfluoroacrylic polymer emulsion using cosolvents. Acetone is shown to be an effective compatibilizing cosolvent to produce self-assembling nanocomposite slurries that form hierarchical nanotextured morphology upon curing. Fabricated coating surface morphology is investigated with an environmental scanning electron microscope (ESEM), and surface wettability is characterized by static and dynamic contact angle measurements. The coatings can be applied to large and/or flexible substrates by spray coating with ease and require no additional surface treatments of commonly used hydrophobic molecules such as fluorosilanes; i.e., the nanocomposites are inherently superoleophobic. The superoleophobic nature of the coatings is also discussed within the framework of Cassie-Baxter and Wenzel wetting theories.

A colloidoscope of colloid-based porous materials and their uses

“…Polydisperse particles, which are unable to crystallize in an ordered matrix, can be used to prepare amorphous assemblies without long-range order ( Figure 3B). 4,82 Simplistic and scalable approaches such as spray coating 83,84 or layer-by-layer assembly 85,86 of particles that are not suitable for crystallization due to high attractive forces or insufficient crystallization time can still be used to prepare disordered assembly structures in an experimentally straightforward way. Indeed, as we discuss in detail in several of the following sections, order is not necessary for every application of CBPM, and controlled disorder may even create desired properties.…”

“…237 A simple spray coating of metal oxide colloids combined with a perfluoroacrylic polymer emulsion or fluorosilane has recently been used to easily create superoleophobic coatings as well ( Figure 14C). 84,215,238 These methods are promising candidates for omniphobic coatings for applications where transparency is not a design criterion, such as for drag reduction in pipelines. polymethylmethacrylate (PMMA).…”

“…(C) An omniphobic coating: (i) SEM of ZnO particles sprayed with perfluoroacrylic polymer emulsion, and (ii) the resulting high oil contact angle. 238 Reproduced with permission from the American Chemical Society.…”

The superhydrophobicity of polymer surfaces: Recent developments

“…One way around this is not to spin at all, but to add other materials and rely solely on electrospray to produce a blobby surface. This has been achieved in various ways 37 with great success, but the surface is not fibrous and so some of the potential benefits are lost.…”

A superoleophobic textile repellent towards impacting drops of alkanes

“…Third, the surface energy of the substrate should be as low as possible [7,8,11]. Due to these quite intricate prerequisites up to now only a few surfaces have been reported on which low surface tension liquids such as hexadecane (γ = 27 mNm -1 ) [12][13][14][15][16], dodecane (γ = 24.9 mNm -1 ) [16,17], decane (γ = 23.4 mNm -1 ) [16], ethanol (γ = 22 mNm -1 ) [9], silicone oil (γ = 22 mNm -1 ) [14] or octane (γ = 21.1 mNm -1 ) [8] show superoleophobicity, meaning apparent contact angles above 150° and low sliding angles.…”