SafeWax: Bio-inspired Fatty Acid-based Coatings Advancing Sustainability and Climate Adaptation in Agriculture

Global warming and climate change pose a critical threat to worldwide agriculture, exposing crops to extreme temperatures and prolonged droughts that compromise yield and quality. In nature, certain plants demonstrate sophisticated waxy cuticles featuring micro- and nanostructures, such as those found on Lotus and Broccoli leaves. These structures create a superhydrophobic layer that serves as a functional interface regulating interactions between plant surfaces and their environment, conferring properties that span from reduced water loss and self-cleaning to optical regulation and pathogen protection. However, most cultivated crops lack such intrinsic protective surface structures, increasing their susceptibility to both abiotic and biotic stresses as climate-related pressures intensify. To bridge this gap, we present SafeWax, a novel bio-inspired fatty acid-based solution engineered to emulate the protective functions of plant cuticles. Applied via spray deposition, SafeWax exploits the self-assembly of safe, biodegradable fatty acids into a hierarchical crystalline coating, whose structure and composition were characterized by synchrotron high-resolution powder diffraction and grazing-incidence X-ray diffraction. Our research demonstrates that SafeWax not only alters surface wetting behavior, rendering plant surfaces superhydrophobic, but also provides multi-functional protection. It exhibits enhanced near-infrared reflectance for passive cooling (lowering leaf temperature by up to 4.5°C) and high intrinsic UV absorption for sunburn protection, all while maintaining up to 95% visible light transmittance to ensure photosynthesis is not impaired. Furthermore, the coating’s superhydrophobicity prevents surface water accumulation and facilitates efficient dew collection, offering a supplemental water source under drought conditions. We confirmed the coating's functional stability under varying thermal and weathering stressors, and validated its performance on diverse substrates, ranging from synthetic model surfaces to cuticles derived from various plant species. SafeWax thus shows promise as a protective surface shield against intensifying climate pressures that may help reduce heat stress and water scarcity, enhancing crop resilience in a warming world.