Download or read book From Gecko Feet to Adhesive Tape written by Wil Mara and published by Cherry Lake. This book was released on 2014-01-01 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Learn about how nature has inspired technological innovations with this book on the similarities between gecko feet and a new adhesive tape. Integrating both historical and scientific perspectives, this book explains how gecko feet inspired the invention of an adhesive. Readers will make connections and examine the relationship between the two concepts. Sidebars, photographs, a glossary, and a concluding chapter on important people in the field add detail and depth to this informational text on biomimicry.

Download or read book From Gecko Feet to Sticky Tape written by Toney Allman and published by . This book was released on 2006-01-01 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: All about the properties of geckos' feet, and a useful product based on them.

Download or read book Surface Construction and Mechanisms of Adhesion in Tokay Gecko Feet and Characterization of a Bio inspired Reversible Adhesive Tape written by Robert A. Sayer and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Several creatures including insects, spiders, and lizards, have developed a unique clinging ability that utilizes dry adhesion. Geckos, in particular, have developed the most complex adhesive structures capable of smart adhesion--the ability to cling on different smooth and rough surfaces and detach at will. These animals make use of on the order of a million microscale hairs (setae) (about 14000/mm2) that branch off into hundreds of nanoscale spatulae. This hierarchical surface construction gives the gecko the adaptability to create a large real area of contact with surfaces. van der Waals forces are the primary mechanism utilized to adhere to surfaces and capillary forces are a secondary effect that can further increase adhesive force. Although a gecko is capable of producing on the order of 20 N of adhesive force, it retains the ability to remove its feet from an attachment surface at will. A man-made fibrillar structure capable of replicating gecko adhesion has the potential for use in dry, superadhesive tapes that would be of use in a wide range of applications. These adhesives could be created using micro/nanofabrication techniques or self-assembly. A fibrillar polyvinylsiloxane (PVS) sample consisting of an array pillars (about 230/mm2) approximately 50 um in diameter, 70 um in height and 60 um center-to-center was compared to an unstructured sample. Structured roughness was found to be more important than random roughness in adhesion. The added roughness of the structured sample increased the hydrophobicity of the surface.

Download or read book Engineering Gecko inspired Adhesives written by Srinivasan Arul Suresh and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The last 20 years have seen considerable interest in bioinspired dry adhesives, based on discoveries regarding the adhesive system of the gecko and some arthropods. Such adhesives typically have the advantage of being reusable, leaving no residue, and allowing control of the adhesion through loading states. However, the number of practical applications of these adhesives remains small. One possible reason is that unlike in mechanical design, where design, simulation, and testing methodologies are all well established, there are significant gaps in all of these phases of engineering as applied to gecko-inspired adhesives. There are a variety of methods and metrics used for evaluating adhesives, often giving differing results, and even in some cases results that do not accurately reflect those observed in practical applications. Even with an accurate evaluation of an adhesive material, refining the design is challenging, as the design and manufacturing methods are typically time-consuming, highly constraining, or both. At the same time, there continues to be growing interest in the use of these adhesives in wide-ranging applications including reusable tapes and bandages; improved and more gentle industrial grippers; and grasping objects in space, where the combination of large objects, low contact forces, and lack of atmosphere make adhesives of particular interest. To address this growing need for improved ability to design and manufacture adhesives tailored to these applications, a three-pronged approach is taken. An improved method for testing gecko-inspired adhesives is presented. Unlike the common testing paradigms published in the literature, which impose a fixed displacement between the adhesive material and a test surface, the proposed testing method uses a series elastic configuration to apply forces to the adhesive. This shift in test control from displacement-space to force-space allows the testing conditions to be aligned to those seen in applications; whether for climbing, grasping, or adhesive tapes, nearly all applications of gecko-inspired adhesives fundamentally involve force-space constraints in normal conditions. It is shown that by testing the adhesives in similar conditions to those observed in use, the measured limit curves better reflect those seen in practice. Further, in cases where the adhesive structures are more complicated, or more integral to the performance of the adhesive--such as the directional, controllable adhesives at the core of this work--force-space testing enables measuring the full capabilities of the adhesive, which in many cases are impossible to measure in displacement-space. With the ability to accurately measure more complex limit curves, spatial variation is investigated as a means to improve the ability to create adhesives with novel parameters. In this case, the property of interest is a high friction ratio, the ratio of friction in a preferred direction to friction in the opposite direction, a property of the natural gecko adhesive system. Taking inspiration from the spatial variation found on the gecko's feet, an adhesive structure with wedges of varying length is developed, modeled, and analyzed. The friction ratio of this adhesive is measured, indicating an improvement of orders of magnitude over the current state of the art. Further, this adhesive structure also demonstrates the possibility of simplifying the adhesive design problem. Rather than developing a single complex feature to provide all of the desired properties, spatial variation permits the development of multiple features that are individually simpler but interact to provide more complex behavior. A discussion of the manufacturing process and associated fabrication constraints for these designed adhesive geometries follows. The process is an extension of a previous manufacturing process developed for making uniform adhesives. This is coupled with methods for directly incorporating adhesives into larger assemblies to create tightly coupled adhesive and sensing systems. Finally, a simplified design framework is presented, synthesizing many of the concepts from the prior sections. The current state of the art in adhesive simulation and modeling, while useful for understanding and explaining various specific aspects of adhesive design, is not adequate for directly analyzing the adhesion of complex adhesive geometries. The framework is intended to be a heuristic that synthesizes concepts from the various models of adhesion to provide useful guidance for thinking about adhesive designs for particular applications.

Download or read book Synthetic Gecko Adhesives and Adhesion in Geckos written by Liehui Ge and published by . This book was released on 2011 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geckos' feet consist of an array of millions of keratin hairs that are hierarchically split at their ends into hundreds of contact elements called "spatula(e)". Spatulae make intimate contacts with surface and the attractive van der Waals (vdW) interactions are strong enough to support up to 100 times the animals' bodyweight. Tremendous efforts have been made to mimic this adhesion with polymeric materials and carbon nanotubes (CNT). However, most of these fall short of the performance of geckos. "Contact splitting principle", based on Johnson-Kendall-Roberts (JKR) theory, predicts that a vertically aligned carbon nanotube array (VA-CNT) will be at least 50 times stronger than gecko feet. Although 160 times higher adhesion was recorded in atomic force microscopy (AFM) measurements, macroscopic VA-CNT patches often show low or even no adhesion to substrates. The behavior of VA-CNT hairs near the contact interface has been explored using a combination of mechanical, electrical contact resistance, and scanning electron microscopic (SEM) measurements. Instead of making the expected end contacts, carbon nanotubes make significant side-wall contacts that increase with preload. Adhesion of side-wall contact CNTs is determined by the balance of adhesion in the contact region and the bending stiffness of the CNTs, thus a compliant VA-CNT array is required to make adhesive patches. Macroscopic patches of compliant VA-CNT array have been fabricated. Patches of uniform array have adhesive strength similar to that of geckos (10 N/cm2) on a variety of substrates and can be removed easily by peeling. When the array is patterned to mimic the hierarchical structures of gecko foot-hairs, strength increases up to four times. VA-CNT-based gecko adhesives are self-cleaning, non-viscoelasticity and give good strength in vacuum. These properties are desired in robotics, microelectronics, thermal management and outer space operations. Current theory still cannot completely explain adhesion of gecko feet. A series of experiments have been carried out to measure adhesion at different temperatures using a single protocol with two species of gecko that had been previously studied (G. gecko and P. dubia). Strong evidence of an effect of temperature was found but the trend was counterintuitive given the thermal biology of geckos and it violated the prediction by van der Waals interactions. Consequently, other factors (e.g., humidity) that could explain the variation in the observed clinging performance were examined. Evidence was found, unexpectedly, that humidity is likely an important determinant of clinging force in geckos. Both van der Waals and capillary forces fail to explain the shear adhesion data at the whole animal scale. Resolution of this paradox will require examination of the physical and chemical interaction at the interface and particular way in which water interacts with substrate and setae at the nanometer scale.

Download or read book Handbook of Contact Mechanics written by Valentin L. Popov and published by Springer. This book was released on 2019-04-26 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book contains a structured collection of the complete solutions of all essential axisymmetric contact problems. Based on a systematic distinction regarding the type of contact, the regime of friction and the contact geometry, a multitude of technically relevant contact problems from mechanical engineering, the automotive industry and medical engineering are discussed. In addition to contact problems between isotropic elastic and viscoelastic media, contact problems between transversal-isotropic elastic materials and functionally graded materials are addressed, too. The optimization of the latter is a focus of current research especially in the fields of actuator technology and biomechanics. The book takes into account adhesive effects which allow access to contact-mechanical questions about micro- and nano-electromechanical systems. Solutions of the contact problems include both the relationships between the macroscopic force, displacement and contact length, as well as the stress and displacement fields at the surface and, if appropriate, within the half-space medium. Solutions are always obtained with the simplest available method - usually with the method of dimensionality reduction (MDR) or approaches which use the solution of the non-adhesive normal contact problem to solve the respective contact problem.

Download or read book Nanotribology and Nanomechanics II written by Bharat Bhushan and published by Springer. This book was released on 2011-06-01 with total page 1017 pages. Available in PDF, EPUB and Kindle. Book excerpt: The comprehensive reference and textbook serves as a timely, practical introduction to the principles of nanotribology and nanomechanics. Assuming some familiarity with macroscopic tribology, the book comprises chapters by internationally recognized experts, who integrate knowledge of the field from the mechanics and materials-science perspectives. They cover key measurement techniques, their applications, and theoretical modelling of interfaces, each beginning their contributions with macro- and progressing to microconcepts.

Download or read book Gecko and Bio inspired Hierarchical Fibrillar Adhesive Structures Explored by Multiscale Modeling and Simulation written by Shihao Hu and published by . This book was released on 2012 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gecko feet integrate many intriguing functions such as strong adhesion, easy detachment and self-cleaning. Mimicking this biological system leads to the development of a new class of advanced fibrillar adhesives useful in various applications. In spite of many significant progresses that have been achieved in demonstrating the enhanced adhesion strength from divided non-continuous surfaces at micro- and nano- scales, directional dependent adhesion from anisotropic structures, and some tolerance of third body interferences at the contact interfaces, the self-cleaning capability and durability of the artificial fibrillar adhesives are still substantially lagging behind the natural version. These insufficiencies impede the final commercialization of any gecko inspired products. Hence here, we have focused our attentions on these critical issues in both (i) the gecko adhesive systems and (ii) the synthetic counterparts. (i) We tested the self-cleaning of geckos during locomotion and provided the first evidence that geckos clean their feet through a unique dynamic self-cleaning mechanism via digital hyperextension. When walking naturally with hyperextension, geckos shed dirt from their toes twice as fast as they would if walking without hyperextension, returning their feet to nearly 80% of their original stickiness in only 4 steps. Our dynamic model predicts that when setae suddenly release from the attached substrate, they generate enough inertial force to dislodge dirt particles from the attached spatulae. The predicted cleaning force on dirt particles significantly increases when the dynamic effect is included. The extraordinary design of gecko toe pads perfectly combines dynamic self-cleaning with repeated attachment and detachment, making gecko feet sticky yet clean. This work thus provides a new mechanism to be considered for biomimetic design of highly reusable and reliable dry adhesives and devices. (ii) A multiscale modeling approach has been developed to study the force anisotropy, structural deformation and failure mechanisms of a two-level hierarchical CNT structures mimicking the gecko foot hairs. At the nanoscale, fully atomistic molecular dynamics simulation was performed to explore the origin of adhesion enhancement considering the existence of laterally distributed CNT segments. Tube-tube interactions and the collective effect of interfacial adhesion and friction forces were investigated at an upper level. A fraction of the vertically aligned CNT arrays with laterally distributed segments on top was simulated by coarse grained molecular dynamics. The characteristic interfacial adhesive behaviors obtained were further adopted as the cohesive laws incorporated in the finite element models at the device level and fitted with experimental results. The multiscale modeling approach provides a bridge to connect the atomic/molecular configurations and the micro-/nano- structures of the CNT array with its macro-level adhesive behaviors, and the predictions from the modeling and simulation help to understand the interfacial behaviors, processes and mechanics of the gecko inspired fibrillar structures for dry adhesive applications.

Download or read book Biological Adhesives written by Andrew M. Smith and published by Springer Science & Business Media. This book was released on 2007-01-12 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many creatures use adhesive polymers and structures to attach to inert substrates, to each other, or to other organisms. This is the first major review that brings together research on many of the well-known biological adhesives dealing with bacteria, fungi, algae, and marine and terrestrial animals. As we learn more about their molecular and mechanical properties we begin to understand why they adhere so well and with this comes broad applications in areas such as medicine, dentistry, and biotechnology.

Download or read book Biomimetics written by Bharat Bhushan and published by Springer. This book was released on 2018-11-03 with total page 995 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents an overview of the general field of biomimetics and biologically inspired, hierarchically structured surfaces. It deals with various examples of biomimetics, which include surfaces with roughness-induced super-phobicity/philicity, self-cleaning, antifouling, low drag, low/high/reversible adhesion, drag reduction in fluid flow, reversible adhesion, surfaces with high hardness and mechanical toughness, vivid colors produced structurally without color pigments, self-healing, water harvesting and purification, and insect locomotion and stinging. The focus in the book is on the Lotus Effect, Salvinia Effect, Rose Petal Effect, Superoleophobic/philic Surfaces, Shark Skin and Skimmer Bird Effect, Rice Leaf and Butterfly Wing Effect, Gecko Adhesion, Insects Locomotion and Stinging, Self-healing Materials, Nacre, Structural Coloration, and Nanofabrication. This is the first book of this kind on bioinspired surfaces, and the third edition represents a significant expansion from the previous two editions.

Download or read book NanoCarbon 2011 written by César Avellaneda and published by Springer Science & Business Media. This book was released on 2012-10-02 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents highlighted results coming up from NanoCarbon2011, a Brazilian Carbon event. The topics cover the latest advances in Brazilian basic and applied research related to different carbon materials. The chapters address reviews on their fundamental and outstanding properties and describe various classes of new promising high-tech applications for carbon materials.

Download or read book Encyclopedia of Nanoscience and Society written by David H. Guston and published by SAGE. This book was released on 2010 with total page 1025 pages. Available in PDF, EPUB and Kindle. Book excerpt: Because of their far-reaching consequences, truly transformative technologies always generate controversy. This encyclopedia covers the ethical, legal, policy, social, economic, and business issues raised by nanoscience.

Download or read book Introduction to Nanoengineering written by Darren J. Lipomi and published by Royal Society of Chemistry. This book was released on 2024-05-10 with total page 457 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multiscale Dissipative Mechanisms and Hierarchical Surfaces written by Michael Nosonovsky and published by Springer Science & Business Media. This book was released on 2008-06-21 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multiscale Dissipative Mechanisms and Hierarchical Surfaces covers the rapidly developing topics of hierarchical surfaces, roughness-induced superhydrophobicity and biomimetic surfaces. The research in these topics has been progressing rapidly in the recent years due to the advances in the nanosciences and surfaces science and due to potential applications in nanotechnology. The first in its field, this monograph provides a comprehensive review of these subjects and presents the background introduction as well as recent and new results in the area.

Download or read book Bioadhesion written by Stanislav N. Gorb and published by Frontiers Media SA. This book was released on 2021-11-01 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sticking Together written by Professor Steven Abbott and published by Royal Society of Chemistry. This book was released on 2020-05-05 with total page 297 pages. Available in PDF, EPUB and Kindle. Book excerpt: This popular science title covers adhesion science in an easily accessible entertaining manner. As well as outlining types of adhesion and their importance in everyday life, the book covers interesting future applications of adhesion and inspiration taken from nature. Ideal for students and the scientifically minded reader this book provides a fascinating introduction to the science of what makes things stick.

Download or read book Bioinspiration and Biomimicry in Chemistry written by Gerhard Swiegers and published by John Wiley & Sons. This book was released on 2012-10-30 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt: Can we emulate nature's technology in chemistry? Through billions of years of evolution, Nature has generated some remarkable systems and substances that have made life on earth what it is today. Increasingly, scientists are seeking to mimic Nature's systems and processes in the lab in order to harness the power of Nature for the benefit of society. Bioinspiration and Biomimicry in Chemistry explores the chemistry of Nature and how we can replicate what Nature does in abiological settings. Specifically, the book focuses on wholly artificial, man-made systems that employ or are inspired by principles of Nature, but which do not use materials of biological origin. Beginning with a general overview of the concept of bioinspiration and biomimicry in chemistry, the book tackles such topics as: Bioinspired molecular machines Bioinspired catalysis Biomimetic amphiphiles and vesicles Biomimetic principles in macromolecular science Biomimetic cavities and bioinspired receptors Biomimicry in organic synthesis Written by a team of leading international experts, the contributed chapters collectively lay the groundwork for a new generation of environmentally friendly and sustainable materials, pharmaceuticals, and technologies. Readers will discover the latest advances in our ability to replicate natural systems and materials as well as the many impediments that remain, proving how much we still need to learn about how Nature works. Bioinspiration and Biomimicry in Chemistry is recommended for students and researchers in all realms of chemistry. Addressing how scientists are working to reverse engineer Nature in all areas of chemical research, the book is designed to stimulate new discussion and research in this exciting and promising field.