Latex-Bridged Inverse Pickering Emulsion for Durable Superhydrophobic Coatings with Dual Antibacterial Activity

There is agreement that every colloidal structure produces its own set of unique characteristics, properties, and applications. A colloidal phenomenon of latex-bridged water in a dimethyl carbonate (DMC) Pickering emulsion stabilized by R202 hydrophobic silica was investigated for its ability to act as a superhydrophobic coating (SHC) for cellulose substrates. First, various emulsion compositions were screened for their stability and droplet size. The final composition was then cross-examined by cryogenic scanning electron microscopy and optical and fluorescent microscopy to verify the colloidal structure. The drying pattern of the coating was investigated by using labeled samples under a fluorescent microscope and by scanning electron microscopy on a paper substrate. After the final ∼3 μm of dry coating was applied, it exhibited superhydrophobicity (advancing contact angle = 155°) and full functionality after 5 min at room temperature (RT). Coated samples maintained superhydrophobicity after 20 abrasion cycles and mechanical integrity after 50 s of water immersion. The SHC-coated paper demonstrated compatibility with a standard laser printer, and the coated paper demonstrated superhydrophobicity after printing. Finally, a propolis/DMC extract was produced and then analyzed by gas chromatography-mass spectroscopy (GC-MS) and infused into the SHC (PSHC). The newly formed PSHC demonstrated its ability to act effectively against E. coli biofilm and S. aureus planktonic cells and reduce their viability by over 90% and 99.99%, respectively.