A research team from Beijing Institute of Technology (BIT) recently made a breakthrough in the study of wettability at the interface of hydrophobic plants.

The study highlighted that surface polarity is the key factor determining the wettability of plant leaf surfaces, challenging the traditional view that micro-nano structures and wax layers are the dominant factors in hydrophobicity. The findings were published in the renowned international journal Langmuir under the title Beyond Microstructures: Surface Polarity as the Key To Reversible Hydrophobicity in Natural Plant Leaves (DOI:10.1021/acs.langmuir.5c05926).

The superhydrophobic characteristics of plant leaves, such as the "self-cleaning" properties of lotus and rice leaves, have long been attributed to hierarchical micro-nano structures and wax coatings. This understanding has been a crucial theoretical basis for the development of biomimetic materials and agricultural applications. However, in practical agriculture, the strong hydrophobicity of crop leaves causes pesticide droplets to easily bounce off and fail to adhere, leading to significant pesticide loss and environmental pollution. Current technologies struggle to achieve controllable and reversible transitions between hydrophobicity and hydrophilicity on leaf surfaces.

Addressing this scientific issue and industry challenge, the research team focused on four typical hydrophobic plant leaves: rice, lotus, reed, and clover. They developed a surface modification strategy using oxygen plasma, achieving reversible switching between hydrophobicity and hydrophilicity on the leaves.

Another significant value of this research lies in its preliminary validation for agricultural applications. In rice fields, the stems of rice plants often form an angle greater than 60 degrees with the horizontal plane. Traditional pesticide droplets tend to bounce off hydrophobic rice leaves, resulting in loss. However, after plasma treatment, rice leaves can effectively spread and retain pesticide droplets even at large angles, significantly improving pesticide utilization. This method also achieves reversible hydrophilicity, allowing subsequent rain or washing to remove pesticide residues and restore the leaf's inherent hydrophobicity, balancing pesticide efficiency with food and environmental safety.

In terms of agricultural applications, this technology offers a new solution for precise pesticide delivery and sustainable agriculture management. If portable, field-applicable plasma generation equipment can be developed, it could substantially reduce pesticide usage and agricultural non-point source pollution, supporting the development of green agriculture. Additionally, this mechanism provides new insights for material design in fields such as self-cleaning surfaces, microfluidic chips, and oil-water separation, with broad interdisciplinary application prospects.

Paper details: ：Guan-chu Liu, Jia-hao Yan, Li Zheng, Xu Han, Long-shuo Gu, Qi-liang Huang, Han-yuan Chen, Sheng Meng, Li-wei Liu, Yun-yun Dai, Xia Liu,* Ye-liang Wang,* and Yuan Huang*，Langmuir., 42(4), 3512 (2026).