Abstract:
Life appeared on Earth at least 3.5 billion years ago. Through evolution, unsustainable species/processes have been weeded out such that the currently biodiversity are all success stories. Effective translation of bio-inspired fundamentals to engineering solutions require identification of dominant, relevant mechanisms that may be hidden in complex and interdisciplinary systems. I will discuss two examples of extracting useful principles from two very different systems.
First, I used spider glue as a model system to conduct a detailed investigation of its humidity responsive adhesion at multiple length scales. Modern orb-web spiders use capture silk to catch and retain prey. Remarkably, the sticky capture silk needs to be sticky in diverse spider habitats that can range from dry and arid to wet and humid. This contrasts with most synthetic adhesives which fail above a critical humidity. On a molecular scale, glue viscosity varies over five order of magnitude with humidity. However, the glue viscosity is similar at the humidity of maximum adhesion, which can be very different, 30-90% relative humidity (RH) for different species. On a macro scale, I found that spider use a combination of capillary instability and environmental humidity to control the size and space of glue droplet on their capture silk. Modulation of bead-on-a-string morphology results in non-linear scaling of capture silk adhesion with glue volume, and can be used to catch different sized prey in their habitat. Second, I will present efforts to understand granular rheology of asymmetric polymeric particles. Granular matter is the second most processed material in industry, after water. Polymeric particles are irregular shaped and often cause bridging, rat-holing in a hopper. We found that use of inorganic nano-particles can significantly improve the processability of polymeric powders. These examples elucidate simple physical principles that dominate the response of these remarkable systems.
Bio:
Dr. Amarpuri graduated with B.Tech in Textile Technology from Indian Institute of Technology, Delhi in 2008. After graduation, he joined the cellulosic research team of Aditya Birla Sc. & Tech. Co. Ltd. in Mumbai, India. He learnt to use scientific fundamentals develop new products and improve quality of existing products. In 2012, he decided to go back to graduate school and joined the PhD programe at the Polymer Science department at The University of Akron, Ohio. He was amazed by the concept of biomimicry – an inter-disciplinary science that takes direct cures from nature to inspire research and development. He used spider glue as a model system to understand the fundamentals of humidity responsive adhesion. In June 2017, He joined Eastman Chemical Co. as a rheologist in the corporate analytical division. He continues to apply biomimicry principles to solve pressing industrial problems.