Synthesis of ZnO/TiO2-Based Hydrophobic Antimicrobial Coatings for Steel and Their Roughness, Wetting, and Tribological Characterization

Abstract

We synthesized novel TiO2/ZnO-phosphate (TP/ZP) and polymethyl hydrogen siloxane (PMHS) based 2-layer hydrophobic coatings with potential antimicrobial properties tuned for application on steel substrates. The mathematical method of topological data analysis was applied to surface roughness data. Wetting characterizations show stable hydrophobic behavior of the 2-layer coated samples. Through tribological characterization, we compare the friction behavior of uncoated steel samples and steel samples coated with different coating materials. The coefficient of friction of uncoated base materials (ranging from 0.221 to 0.269) and the 2-layer hydrophobic coatings (ranging from 0.234 to 0.273) indicate that the coatings confer hydrophobic properties to the substrates without a notable change in the friction behavior. We observed the correlations between the wetting and friction behaviors and average roughness of the coated samples. Analysis of the micrographs of the scratched surfaces reveals preliminary information about the durability and abrasion resistance of the coatings.

From superhydrophilicity to superhydrophobicity: high-resolution neutron imaging and modeling of water imbibition through porous surfaces treated with engineered nano-coatings

“…The surface treatment with the coating formulation systematically filled the pores and created the desired roughness at the surface of the specimen. The coating layer was composed of sharp edge crystals that suffered from hydrothermal cracks, which further enhanced the roughness and created conditions that favored obtaining high water contact angles 2 . There is no distinct difference between the hydrophilic surface visible in Fig.…”

“…Coatings play a significant role in protecting various materials from decay and deterioration 1 . Thin phosphate-based coatings that repel water, decompose organic and inorganic compounds, and provide anticorrosive properties are an innovative idea that combines crucial material protection potential and environmental benefits 2 .…”

“…Surfaces that repel water have contact angles higher than 90° and are considered hydrophobic. This state can be further divided into overhydrophobic and superhydrophobic surfaces, which can be achieved by introducing hierarchical roughness 2 . Either nano- or micro-particles are needed to elevate the surface into the overhydrophobic state, and a combination of micro- and nano-roughness is necessary to achieve the superhydrophobic state.…”

A Review of Antimicrobial Polymer Coatings on Steel for the Food Processing Industry

“…Various approaches to control and prevent the colonization and growth of biofilm on steel have been discussed in the literature: Steel composition (alloying) [ 27 , 28 , 29 , 30 ]; Electrochemical, chemical, or physical modification of the steel surface: metal coatings (Cu-coated steel [ 31 , 32 ] Ag-coated steel [ 33 , 34 ], Cu-Co-coated steel [ 34 ]) laser irradiation [ 35 ], etching and plasma [ 36 , 37 , 38 , 39 ] or other introduction of modifiers into the surface; Application of antimicrobial coatings [ 40 , 41 , 42 , 43 , 44 ]. …”

“…Steel composition (alloying) [27][28][29][30]; • Electrochemical, chemical, or physical modification of the steel surface: metal coatings (Cu-coated steel [31,32] Ag-coated steel [33,34], Cu-Co-coated steel [34]) laser irradiation [35], etching and plasma [36][37][38][39] or other introduction of modifiers into the surface; • Application of antimicrobial coatings [40][41][42][43][44]. Three primary directions stand out for antimicrobial polymer coating strategies [4]:…”