Biomimicry: Recent updates on nanotechnology innovations inspired by nature creations

: Nature mimicry rather, biomimicry is one such field being considered for the backbone of the most astounding inventions in recent science and technology. Biomimicry combined with nano-technology developed many sustainable solutions to satisfy problems existing in daily life. In this article, we also explore the individual concepts of biomimicry and nano-technology and then the combination of the both. The current review mainly focusses of nano innovations inspired by lotus leaf, gecko feet, butterfly wings, shark skin and peacock spider. We then look at the biological structures (more in nano-dimensions) from the entrenched interference patterns found on the butterfly wings inspiring in the development of display technologies to the self-cleaning properties of lotus that has resulted in the synthesis of nano materials having self-cleaning properties. In addition, insects like spiders which have inspired the most important inventions like optical devices, sensors, are also investigated. The challenges faced while implementing the biomimetic approach into technology are explained. We have also tried to shed light on the solutions which can tackle these challenges and issues. Some of the very important reasons why this approach can be a boon to humanity namely helping in the control of climate change, environmental degradation and pollution by offering sustainable solutions are also elucidated.

Adhesive contact of rough brushes

The adhesive contact between a rough brush-like structure and an elastic half-space is numerically simulated using the fast Fourier transform (FFT)-based boundary element method and the mesh-dependent detachment criterion of Pohrt and Popov. The problem is of interest in light of the discussion of the role of contact splitting in the adhesion strength of gecko feet and structured biomimetic materials. For rigid brushes, the contact splitting does not enhance adhesion even if all pillars of the brush are positioned at the same height. Introducing statistical scatter of height leads to a further decrease of the maximum adhesive strength. At the same time, the pull-off force becomes dependent on the previously applied compression force and disappears completely at some critical roughness. For roughness with a subcritical value, the pressure dependence of the pull-off force qualitatively follows the known theory of Fuller and Tabor with moderate modification due to finite size effect of the brush.

Self-Cleaning and Controlled Adhesion of Gecko Feet and Their Bioinspired Micromanipulators

ABSTRACTBioinspired micromanipulators have been made based on gecko dynamic self-cleaning mechanism. Various particles such as spherical SiO2/polystyrene, and short fibrous glass can be captured, transmitted and dropped on glass substrate with precisely predesigned patterns, by using the micromanipulator with the help of atomic force microscope (AFM). It has been demonstrated that particle-pad interface and particle-substrate interface exhibit diverse adhesion behaviors under different z-piezo retracting speed. The particle-substrate adhesion increases faster than the particle-pad adhesion with increasing the detaching velocity, which makes it possible to manipulate the particles by adjusting the retreating speed only. Probability tests was performed to better choose suitable parameters for picking and dropping operations. This work provides a potential solution to manipulation of micro/nano particles for precise assembly.

Gecko Feet as a Bio Prototype for the Use of Dry Adhesion in Engineering Decisions

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.

Biomimetic self-cleaning surfaces: synthesis, mechanism and applications

With millions of years of natural evolution, organisms have achieved sophisticated structures, patterns or textures with complex, spontaneous multifunctionality. Among all the fascinating characteristics observed in biosystems, self-cleaning ability is regarded as one of the most interesting topics in biomimicry because of its potential applications in various fields such as aerospace, energy conversion and biomedical and environmental protection. Recently, in-depth studies have been carried out on various compelling biostructures including lotus leaves, shark skins, butterfly wings and gecko feet. To understand and mimic their self-cleaning mechanisms in artificial structures, in this article, recent progress in self-cleaning techniques is discussed and summarized. Based on the underlying self-cleaning mechanisms, the methods are classified into two categories: self-cleaning with water and without water. The review gives a succinct account of the detailed mechanisms and biomimetic processes applied to create artificial self-cleaning materials and surfaces, and provides some examples of cutting-edge applications such as anti-reflection, water repellence, self-healing, anti-fogging and micro-manipulators. The prospectives and directions of future development are also briefly proposed.

Bioinspired Composite Materials: Applications in Diagnostics and Therapeutics

Evolution-optimized specimens from nature with inimitable properties, and unique structure–function relationships have long served as a source of inspiration for researchers all over the world. For instance, the micro/nanostructured patterns of lotus-leaf and gecko feet helps in self-cleaning, and adhesion, respectively. Such unique properties shown by creatures are results of billions of years of adaptive transformation, that have been mimicked by applying both science and engineering concepts to design bioinspired materials. Various bioinspired composite materials have been developed based on biomimetic principles. This review presents the latest developments in bioinspired materials under various categories with emphasis on diagnostic and therapeutic applications.

Numerical Evaluation of Improvements in Thermal Barrier Coating Adhesion by Adoption of Plasma Treatment and Biomimicry

Thermal Barrier Coatings or TBCs for short, are an imperative part of the thermal protection system of expensive equipment and machinery in the automobile and aeronautics industries. However, the problem of adhesion has plagued the TBC field for years, leading to catastrophic failures in critical TBC systems. Efforts to chemically improve bond strength have not been entirely successful, so the other efficient way to do this would be some kind of mechanical interlocking that occurs at micro/nano scales. This work deals with the improvement of adhesion in TBC systems by numerical simulation and bench-marking of micro-geometric surface features that has been synthesized or reproduced in a laboratory environment through mechanical or electrochemical operations. For this, several geometries that benefit mechanical interlocking, and consequently improvements in mechanical ‘adhesion’ in TBCs have been compared. To simulate the mechanical and thermal loading on the micro geometries and to observe their effect, the commercial finite element software COMSOL was used. An analogy was drawn between the biological, Van der Waals dry adhesion mechanism in Gecko feet and that in the top surface of the thermally grown oxide (TGO) layer in TBC since the ‘mushroom head geometry’ in the Gecko feet provides improved adhesion (as much as 10 folds) compared to other geometries (spatular head, spherical head, or plain triangular crevices). An affordable synthesis process, termed “Electrolytic Plasma Processing (EPP)” for recreating this specific geometry, is also proposed and its utility briefly discussed.