The research objective of this award is to identify the role of nanoparticles secreted by ivy for high strength surface adhesion. We propose to use insight from this natural system to elucidate the principles that govern the extraordinary affixing capability of the ivy. The specific aims of this study are centered around characterization of the physical and chemical properties of the ivy nanoparticles and the adhesive matrix. We will also systematically study the amount of nanoparticles present in the adhesive matrix and their contribution to the overall adhesive properties. These efforts will not only improve our understanding of the fundamental role of nanoparticles in surface affixing for biological systems, but also inspire bio-mimetic approaches to design high strength adhesives. Deliverables include quantitative methods to introduce nanoparticles for high strength adhesives, and discovery of fundamental principles of the nature to use nanoparticles for surface affixing.
If successful, the results of this research will provide an opportunity to design and create bio-inspired adhesives that are capable of generating large adhering forces and are water resistant. The results will be significant in terms of both understanding fundamental biological affixing mechanisms and developing new bio-inspired nano-materials. Example applications include strong adhesive materials for aerospace, underwater, and biomedical applications. The results will be disseminated to allow the creation of commercial adhesives that have strong and tunable adhesive strength. Graduate and undergraduate engineering students will be directly involved in this research and gain experiences on interdisciplinary research experiences on bio-inspired materials and nanotechnology. This project will also support pre-scholar high school students and minority students in summer research. The lab conducting this research is a representative lab for diversity program at the university, and will use this project as a demo project for diversity summer program for high school students each year.
For many years, people have realized the potential benefits to understand and utilize the adhesive properties of natural systems for engineering innovation. While this has led to intense scrutiny of gecko footpad setae, adhesive proteins secreted by mussel, and viscid silk spun by spiders, the physical properties, which allow English ivy (Hedera helix) to affix to a surface, have been widely neglected. Since the yellowish matter secreted by the adventitious roots of English ivy was discovered by Charles Darwin in 1876 and was believed to play a crucial role in generating high-strength adhesion, little progress has been made in understanding the underlying molecular mechanisms. Our group first discovered that spherical nanoparticles abundantly exist in the secreted adhesive of English ivy and intuitively, these nanoparticles are believed to play a direct role in facilitating the surface affixing and are fundamental building blocks for the high-strength adhesive. In this project, we studied the role of the nanoparticles secreted by ivy for high-strength surface adhesion. The physical and chemical properties of ivy nanoparticles and the adhesive matrix have been thoroughly characterized, respectively. The principles that govern the extraordinary affixing capability of English ivy have been elucidated through studying this natural system. We found that the small size allows ivy nanoparticles fit into and conform to a variety of different surface topologies; their chemical composition generates large cumulative forces including van der Waals forces for the initial adhesion process; and their chemical composition also allows for further cross-linking of the secreted adhesive. These efforts not only improve our understanding of fundamental role of nanoparticles in surface affixing for biological systems, but also inspire novel approaches to design engineering high-strength adhesives. Results of this project advance knowledge and understanding of the relationships between surface and coating properties of nanomaterials. In addition to advance knowledge of adhesive science, this research also advances fundamental knowledge about biological secretion. The findings not only revolutionize our understanding of plant affixing or climbing, but also have a broader impact on bio-inspired nanomaterials, and non-traditional adhesive science. The impact of this project is significant in terms of both understanding fundamental biological mechanisms and developing new bio-inspired nano-materials. Society benefits on a broader scale as the results spill over into practical bio-engineering and biomedical applications. The educational impact of this project is also broad and pervasive for the interdisciplinary field of nano-materials and bio-inspired materials. This project creates a promising frontier in bio-inspired nano-materials for surface adhesion.
