Super-hydrophobicity and oleophobicity of a surface means that water and oil liquids have a contact angle on a surface greater than or equal to 150°, low contact angle hysteresis and a sliding angle of less than 10°. Synthetic hydrophobicity and oleophobicity are applied to a surface to make the surface self-cleaning, anti-corrosive and anti-fouling to a variety of possible contaminants. Here, we report an aqueous suspension of micro-particles for the fabrication of super-hydrophobic and oleophobic substrates. In our experiments, the deposition of hollow glass spheres on a glass substrate provides the necessary increased microscale topography needed for super-hydrophbicity. By depositing aqueous suspended glass spheres on a substrate, we can bake off the aqueous media at high temperatures leaving behind fused micro-glass topography. Nano-roughness is then added by assembling monolayers of n-octadecyltrimethoxysilane and (tridecafluro-1,1,2,2tetrahydrooctyl) triethoxy silane. The hydrophobic chains on our self-assembled monolayers provide the necessary functionality on the structures to allow for Cassie-State formation at an air/liquid/ solid interface (i.e. hydrophobicity of water). Our substrates are repellant to water with static contact angles in 140-150° range. The substrates also repel oily substances with a static contact angle of &gt;100<sup>o</sup>. Dynamic contact angle measurements on our modified surfaces showed low contact angle hysteresis, with only a 5° between advancing and receding contact angles. Low hysteresis suggests that the liquid of interest will symmetrically roll of the substrate rather than spread and/or slide down the substrate. Fusion and chemical cross-linking of our micro and nano- topography affords necessary durability to our substrates as they maintain their super-hydrophobic/oleophobic properties after washing and drying of the substrate. In this project, we report a simple two-step method for preparing super-hydrophobic and oleophobic substrates on a large scale.

Superhydrophobicity and oleophobicity via increased modified surface topography

249th National Meeting (2015)

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