Dynamics of leaves with different wettability due to raindrop impact

PI：Jung，Sunghwan提案编号：1604424根据表面被水润湿的难易程度，它可以是亲水性或疏水性的。拟议的研究受到生物表面的启发，如树叶，在其生命周期中表现出不同的润湿行为，并随着天然或人造污染物与其表面相互作用而从疏水性变为亲水性。研究水滴溅在树叶上的动态变化是如何由于表面特征的变化而变化的，这对于理解早期灾难性的树叶损失和开发避免它的方法是很重要的。这可能对预测食物和森林资源的水平有进一步的影响。生物学家和生物化学家以前关于树叶脱落的工作大多集中在空气污染物对树叶表面的急性化学影响上。然而，无论是物理机制的叶片转向亲水性和亲水性叶片在雨滴响应的动力学方面还没有得到很好的理解，这可能显着有助于灾难性的叶片损失后，雨。PI建议调查叶子和叶子之间的相互作用。的润湿性，弹性，和下降蔓延，灵感来自雨滴影响树叶的性质。首先，将探索从疏水叶向亲水叶转变的机制。其次，在弯曲的基板上的液滴的传播动力学将制定宏观和微观的润湿性和下降速度方面，这将允许估计的冲击力和液滴传播半径的叶。最后，一片叶子？的机械模量和极限强度的特点，以了解弯曲和扭转变形的叶片后下降的影响。PI将为残疾学生追求个人和教育利益。作为一项教育目标，公共政策研究所将制定研究方案，帮助残疾学生克服目前教育系统中由于社会和交流技能受损而遇到的困难。一个被提议的同伴伙伴计划是为自闭症或其他社会障碍的学生设计的，让他们沿着典型的同伴在结构化的环境中接受实验室研究。一个包容性的环境将为学生提供结构化的研究机会，这将有助于培养与同龄人有效沟通和合作所需的信心和能力，并最终成为未来的工程师或科学家。

PI: Jung, SunghwanProposal Number: 1604424Based on how easy it is for a surface to be wetted by water, it can be hydrophilic or hydrophobic. The proposed research is inspired by biological surfaces, like leaves, that exhibit different wetting behavior in their lifetime, and turn from hydrophobic to hydrophilic as natural or man-made pollutants interact with their surface. Investigating how the dynamics of drops splashing on leaves change because of changes on surface characteristics is important for understanding early catastrophic leaf loss and developing methods to avoid it. This can have further implications on predicting levels of food and forest resources.Most of the previous work done by biologists and biochemists about shedding of leafs, has focused on acute chemical effects of air contaminants on leaf surfaces. Nevertheless, both the physical mechanism of a leaf turning hydrophilic and the dynamical aspects of hydrophilic leaves in response to raindrops are not well understood, which may significantly contribute to catastrophic leaf loss after rain. The PI proposes to investigate the interplay between a leaf?s wettability, elasticity, and drop spreading, inspired by a raindrop impacting a leaf in nature. First, the mechanism of transitioning from hydrophobic to hydrophilic leaves will be explored. Secondly, the spreading dynamics of a droplet on a curved substrate will be formulated both macroscopically and microscopically in terms of wettability and a falling speed, which will allow the estimation of an impact force and drop-spreading radius on the leaf. Finally, a leaf?s mechanical moduli and ultimate strengths will be characterized, in order to understand bending and torsional deformations of a leaf upon drop impact. The PI will pursue personal and educational interests for students with disabilities. As an educational objective, the PI will develop research programs that assist disabled students in overcoming the difficulties encountered in the current educational system, due to impaired social and communication skills. A proposed peer-buddy program is designed for students with autism or other social impairments by exposing them to laboratory research along with typical peers in structured environments. An inclusive environment would provide the students with structured research opportunities, which would help to develop the confidence and capacity needed to effectively communicate and collaborate with their peers, and eventually become future engineers or scientists.