Papers by Keyword: Biomimetics Approach

Abstract: The focus of this review is to outline the remarkable ability of the gecko to climb surfaces vertically, at tremendous speed (over 1 m/s) using van der Waals forces (one of nature’s amazing “sticking and unsticking” directional dry adhesion design) as well as contact splitting mechanism. Further, the elasticity of the hairs conforming to the topology of the surface and hence contributing to an increased adhesion force is discussed, apart from the applications of gecko feet bio-inspired solutions. Such applications are in areas as diverse as, and not restricted to, climbing vertically and horizontally on glass surfaces; fitting televisions and computers on the walls; in robots for the inspection and maintenance of installations in space stations and self-cleaning surfaces. By this review, we hope to inspire and motivate the current generation of engineers to study, mimic and abstract the fundamental hierarchical structures as well as the incredible dry adhesion principles (as closely as is possible) objects of nature. This approach will help in improving upon the existing methods to produce gecko feet-like materials with dry adhesion as well as self-cleaning properties. Such refinement strategies can also include the development of hybrid structures utilizing a combination of designs found in other organisms in Mother Nature (for e.g., the mushroom-shaped structure found in the beetle). This requires improvements in the fundamental hierarchical arrangement of the gecko feet-like hairs and their inter-facial interactions with model substrata. Also, the mechanical deformations of the different gecko feet-like materials as well as how sliding velocity impacted adhesional and frictional phenomena should be studied and better understood. This will enable the engineer to develop better gecko feet-like adhesives.

Abstract: In bio-systems, nano-composites with complex micro-structures are formed by self-assembly only using low energy at room temperature. If these mechanisms of biological tissue are identified, we can possibly propose a new process to fabricate composites by mimicking tissue formation in vivo. As a bio-material, we paid attention to bio-tissue reinforced with collagen fibrils. Collagen fibrils are of baculiform; Thus the self-assembly process through liquid crystalline transition has been proposed by a French group [1]. In the present study, factors controlling liquid crystalline transition, e.g. concentration and pH, are discussed using collagen solution. When liquid crystalline phase is produced, aligned molecules exhibits optical anisotropy. This anisotropy was observed with a polarized optical microscopy (POM). By observations with POM, development of cholesteric phase in collagen solution was clarified.