Avinash Baji
Singapore University of Technology and Design, Singapore
Title: Bioinspired hierarchical structures obtained using electrospinning enabled techniques
Biography
Biography: Avinash Baji
Abstract
Natural materials and composites display superior mechanical properties compared to its constituent materials. For example, bones and shells although composed of brittle minerals and soft proteins display high toughness and strength. This is attributed to the organization and structuring of their constituent materials within the composite. Mimicking the size, geometry and the structural design of natural materials can be useful to design and develop new class of synthetic materials. Recently, researchers have used electrospinning to fabricate bio-inspired materials that have found applications in wide variety of fields. For instance, electrospinning is used to fabricate fibers with controllable composition and arrangement such that they closely mimic the natural hierarchical structures for development of functional fibers and membranes that display special wettability. In this study, we used electrospinning to fabricate hierarchical fibrous structures for dry-adhesive applications. These fibers mimic the dry-adhesive mechanisms prevalent in nature, which enables certain animals and insects to scale vertical walls. Briefly, the fibers are electrospun on the surface of a porous anodized aluminum oxide template (AAO). The AAO template with the fibers is then heated above the glass transition temperature of the polymer. This enables the polymer to flow into the pores of the AAO resulting in the formation of sub-nano structures on the surface of the fibers. These hierarchical structures closely mimic the ‘hairy’ structures found on the feet of certain animals. We then investigate the shear and normal adhesion performance of these samples using a tensile tester and atomic force microscope (AFM). The normal and shear adhesion results reveal that these samples adhere to various surfaces including glass and metals. The durability of the adhesive was also verified by repeating AFM adhesion measurements over 1000 consecutive cycles. The normal pull-off force was seen to be constant over 1000 attachment-detachment cycles. These results show the potential of using these electrospun fibers for dry-adhesive applications.