Development of Durable Superhydrophobic Polymer Composite Coatings for Self-Cleaning and Oil-Water Separation Applications

Abstract

In current work, SiO2 nanoparticles embedded linear low density polyethylene (LLDPE) superhydrophobic coatings on glass and filter paper substrates were fabricated using dip-coating and solution casting technique techniques. Porosity of SiO2 nanoparticles coupled LLDPE superhydrophobic coatings was also varied using non-solvent (ethanol) by employing phase separation method. Surface morphology, water contact angle, self-cleaning, oil-water separation, and water-repellency of coatings were characterized. Furthermore, the stability of these coatings was also evaluated by conducting thermal, chemical and mechanical stability tests at perturbation conditions. Along with, comparative studies of porous and non-porous LLDPE/SiO2 coatings on their performances were presented in the current work. By creating porosity and/or embedding SiO2 nanoparticles in to LLDPE matrix, superhydrophobicity is achieved with water contact angle of 170° and sliding angle of 3.8°. Their superhydrophobic property is also maintained after annealing in temperature range from 40 to 120 °C. Water jet impact test reveals the excellent water repellent nature of coatings. Non-porous coatings exhibit more stability in pH range from 4 to 9 than porous coatings. By abrasion test with micro-fiber cloth and tape peeling tests, it is observed that porous coatings are more durable than non-porous coatings. Additionally, waterdrop impact dynamics for the superhydrophobic coatings were also studied. Further, efficiency and reusability of coated filter papers to remove oil from oil-water mixture were also characterized. Coatings show their excellent oil-water separation application with 99.9% oil recovery. Coatings also exhibit the excellent self-cleaning property. These aforesaid coatings have great industrial applications.