Fabrication and characterization of superhydrophobic coatings on cotton fabrics using silica nanoparticles for self-cleaning applications

The marvelous self-cleaning properties of lotus leaves and their superhydrophobic nature inspire the researchers to mimic such functionalities on cotton fabrics. The present work aimed to prepare and characterize true non-sticky superhydrophobic properties on cotton samples. The required combination of micro and nanostructure roughness was achieved by depositing the silica nanoparticles (SiNPs) on cotton surfaces by dip-coating method. To enhance adhesion and durability of silica particles with cotton, SiNPs were functionalized with 3-Aminopropyltriethoxysilane (APTES) before deposition. The surface energy of SiNPs coated cotton samples was lowered by functionalizing with 1H, 1H, 2H, 2H-Perfluorooctyltriethoxysilane (PFOTS). The morphology, surface chemistry and wettability characterizations of prepared samples were performed by scanning electron microscope (SEM), energy dispersive X-ray analysis (EDX) and contact angle measurement system (goniometer) respectively. SEM micrographs revealed the nice decoration of SiNPs (having particles size range 90-150 nm) on the cotton fibers leaving to the hierarchical roughness. The EDX analysis confirmed the coatings of SiNPs and PFOTS. Contact angle measurements exhibited the superhydrophobic nature of prepared surfaces by static water contact angle of 157±2° and sliding angle of less than 5. The functionalized SiNPs/PFOTS cotton fabrics can effectively be used for self-cleaning applications.