Sustainable Plant-Based Water Repellent Coatings Using Hydrophobic Pine and Palm Pollen

Abstract

The environmental concerns associated with plastic and fluorocarbon-based materials have driven the search for sustainable options, particularly in the development of highly water-repellent coatings. Plant-based materials offer a promising solution due to their biodegradability and sustainability. In this study, we developed highly water-repellent coatings using treated pine and palm pollen. Superhydrophobicity was achieved by integrating a hydrophobic plant-based wax with a micro-scale rough structure formed by the pollen. To enhance their surface chemistry, the two pollen species underwent acid treatment, which effectively removed proteins and altered the wettability of the sporopollenin-based structures. The modified pollen was then combined with two plant-based waxes, carnauba and soybean, to fabricate the final coatings. The resulting surfaces demonstrated remarkable water repellence, achieving the highest water contact angles of ∼158° and sliding angles of <6° with the pine pollen/carnauba wax formulations. In contrast, the palm pollen/carnauba wax formulations achieved the highest water contact angle of ∼151° and sliding angle of 13°. Furthermore, this study investigates the influence of both broken and unbroken pollen structures on coating performance. These results demonstrate the potential of plant-derived materials as environmentally friendly alternatives for water-repellent coating applications.