Download or read book How Surface Roughness Affects Adhesion written by Antoine Sanner and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: At atomic scales, all molecules attract each other, but macroscopic objects usually do not stick.The explanation for this apparent paradox is that most surfaces are rough, so that elastically stiff objects only touch on the top of their asperities. Geckos and insects have compliant fibrillar structures or soft pads at the tip of their feet that conform to surface roughness, sustaining enough adhesion to climb vertical walls. Understanding the role of surface roughness in adhesion is a challenge because surfaces exhibit roughness down to the atomic scale. In this thesis, my collaborators and I investigate the effect of surface roughness on adhesion in both stiff and compliant contact systems. I model adhesion theoretically, and I help experimentalists analyze surface topography over multiple scales. The combination of my new models and of the comprehensive surface topography characterization by Abhijeet Gujrati (University of Pittsburgh), allows us to unravel the role of surface roughness in adhesion experiments. Stiff materials do not stick because roughness prevents most of the surfaces to come into the range of molecular attraction. A recent theory quantifies this effect based on an approximate expression for the distribution of interfacial gaps near the contact edge. Joe Monti (Johns Hopkins University) and I benchmark this expression against gap distributions extracted from finely resolved numerical simulations. The theory is valid provided that adhesive stresses are weak and act over a range shorter than a geometrical parameter determined by small-scale roughness. Elastically soft (jelly-like) objects stick because the elastic penalty to deform into intimate contact is small compared to the gain in surface energy. However, theories based on this simple thermodynamic argument cannot explain the fact that in experiments, the force measured during retraction is often much higher than during indentation. This adhesion hysteresis can be caused by material specific irreversibility or elastic instabilities triggered by surface roughness. The role of these instabilities in adhesion hysteresis remains poorly understood because existing numerical and theoretical models cannot account for realistic roughness in soft contacts. I introduce an efficient crack-perturbation model for the contact of rough spheres, enabling large scale simulations with realistic surface roughness. By clarifying the link between adhesion hysteresis and classic pinning problems (for example fracture of heterogeneous materials and wetting angle hysteresis), this model allows me to derive a simple theoretical model linking adhesion hysteresis to surface roughness. In combination with the characterization of surface roughness over multiple scales, my models shed light on the role of elastic instabilities in adhesion experiments. Surfaces are rough from the macroscopic scale down to the atomic scale, and the lack of comprehensive roughness characterization is the major obstacle towards bringing theory and experiments together. Abhijeet Gujrati and collaborators measured the roughness of four diamond coatings over eight decades of length scales, enabling the application of adhesion theories on experiments performed with these samples. Besides the experimental challenge of determining roughness down to the atomic scale, an additional obstacle to the documentation of roughness is the technical complexity of established multiscale roughness measures such as the power spectral density. My collaborators and I address this problem by introducing the scale-dependent roughness parameters (SDRPs), a new analysis framework that is easy to interpret and to implement. This new analysis, together with several established techniques, is available to use through our web-service contact.engineering. We thereby encourage the community to measure, analyze and publish roughness over multiple length scales. The SDRP analysis computes the fluctuations of slopes and curvatures as a function of the lateral length scale. Slopes and curvatures are important ingredients for rough contact theories, but it remains unclear at which scales they matter. Luke Thimons (University of Pittsburgh) and I show that in macro-scale contacts between ruby spheres and diamond coatings, the roughness that critically affects adhesion is between lateral length scales of 43~nm to 1.8~μm. The large-scale cutoff is related to the finite radius of the spherical indenter, while the unimportance of small scales is due to plastic deformations and the long range of the adhesive interaction (5~nm). To determine the critical range of length scales, as well as the parameters of the adhesive interaction, we analyzed the experimental pull-off forces by combining surface topography characterization and numerical simulations. Adhesion is critical in applications such as microelectromechanical systems (MEMS), soft robotics and skin adhesives. Our insights provide guidance for practitioners which scales of roughness to control in order to tune adhesion, and our framework for surface topography characterization will allow a better overall understanding of surface topography across the community

Download or read book Sliding Friction written by Bo N.J. Persson and published by Springer Science & Business Media. This book was released on 2013-03-14 with total page 465 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sliding friction is one of the oldest problems in physics and certainly one of the most important from a practical point of view. The ability to produce durable low-friction surfaces and lubricant fluids has become an important factor in the miniaturization of moving components in many technological devices, e.g., magnetic storage, recording systems, miniature motors and many aerospace components. This book will be useful to physicists, chemists, materials scientists, and engineers who want to understand sliding friction. The book (or parts of it) could also form the basis for a modern undergraduate or graduate course on tribology.

Download or read book Surface Treatment in Bonding Technology written by Anna Rudawska and published by Academic Press. This book was released on 2019-04-15 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface Treatment in Bonding Technology provides valuable advice on surface treatment methods, modern measuring devices, and the appropriate experimentation techniques that are essential to create strong joints with a reliable service life. The book's focus is on the detailed and up-to-date analysis of surface treatment methods for metallic and polymer substrates. An analysis of factors affecting the surface preparation stage, together with advice on selection, is also provided. Essential theory is combined with experimentation techniques and industry practice to provide a guide that is both practical and academically rigorous. Including a general introduction to bonding, as well as coverage of mechanical, chemical and electrochemical methods, this book is the ideal primer for anyone working with or researching adhesive bonding. Provides detailed descriptions of surface treatments and their mechanisms that will help readers build a deep understanding of these fundamental techniques Includes a thorough survey of recent advances in research in surface treatments of metals and polymers Provides technical advice on experimental testing methods throughout the book

Download or read book Adhesive Joints written by K.L. Mittal and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 912 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume documents the proceedings of the International Symposium on Adhesive Joints: Formation, Characteristics and Testing held under the auspices of the Division of Polymer Mater ials:Science and Engineering of the American Chemical Society in Kansas City, MO, September 12-17, 1982. There is a myriad of applications (ranging from aerospace to surgery) where adhesives are used to join different materials, and concomitantly the understanding of the behavior of adhesive joints becomes very important. There are many factors which can influence the behavior of adhesive joints, e.g., substrate preparation, in terfacial aspects, joint design, mode of stress, external environ ment, etc., and in order to understand the joint behavior in a holistic manner, one must take due cognizance of all these germane factors. So this symposium was planned to address not only how to make acceptable bonds but their characterization, durability and testing were also accorded due consideration.

Download or read book Adhesive Properties of Ice written by Hans Helmut Gunter Jellinek and published by . This book was released on 1957 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Surface effects in adhesion friction wear and lubrication written by Donald H. Buckley and published by Elsevier. This book was released on 1981-01-01 with total page 643 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface effects in adhesion, friction, wear, and lubrication

Download or read book Ice Adhesion written by K. L. Mittal and published by John Wiley & Sons. This book was released on 2020-12-15 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique book presents ways to mitigate the disastrous effects of snow/ice accumulation and discusses the mechanisms of new coatings deicing technologies. The strategies currently used to combat ice accumulation problems involve chemical, mechanical or electrical approaches. These are expensive and labor intensive, and the use of chemicals raises serious environmental concerns. The availability of truly icephobic surfaces or coatings will be a big boon in preventing the devastating effects of ice accumulation. Currently, there is tremendous interest in harnessing nanotechnology in rendering surfaces icephobic or in devising icephobic surface materials and coatings, and all signals indicate that such interest will continue unabated in the future. As the key issue regarding icephobic materials or coatings is their durability, much effort is being spent in developing surface materials or coatings which can be effective over a long period. With the tremendous activity in this arena, there is strong hope that in the not too distant future, durable surface materials or coatings will come to fruition. This book contains 20 chapters by subject matter experts and is divided into three parts— Part 1: Fundamentals of Ice Formation and Characterization; Part 2: Ice Adhesion and Its Measurement; and Part 3: Methods to Mitigate Ice Adhesion. The topics covered include: factors influencing the formation, adhesion and friction of ice; ice nucleation on solid surfaces; physics of ice nucleation and growth on a surface; condensation frosting; defrosting properties of structured surfaces; relationship between surface free energy and ice adhesion to surfaces; metrology of ice adhesion; test methods for quantifying ice adhesion strength to surfaces; interlaboratory studies of ice adhesion strength; mechanisms of surface icing and deicing technologies; icephobicities of superhydrophobic surfaces; anti-icing using microstructured surfaces; icephobic surfaces: features and challenges; bio-inspired anti-icing surface materials; durability of anti-icing coatings; durability of icephobic coatings; bio-inspired icephobic coatings; protection from ice accretion on aircraft; and numerical modeling and its application to inflight icing.

Download or read book Mechanics of Hysteretic Adhesive Elastic Mechanical Contact Between Rough Surfaces written by Haneesh Kesari and published by Stanford University. This book was released on 2011 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: In experiments that involve contact with adhesion between two surfaces, as found in atomic force microscopy or nanoindentation, two distinct contact force (P ) vs. indentation-depth (h) curves are often measured depending on whether the indenter moves towards or away from the sample. The origin of this hysteresis is not well understood and is often attributed to moisture, plasticity or viscoelasticity. We present experiments, atomistic simulations and continuum mechanics models that will show that hysteresis can exist without these effects, and that its magnitude depends on surface roughness. We explain the observed hysteresis as the result of a series of surface instabilities, where the contact area grows or recedes by a finite amount. We also demonstrate that when this is the case material properties can be estimated uniquely from contact experiments even when the measured P -h curves are not unique. The hysteresis energy loss during contact is also a measure of the adhesive toughness of the contact interface. We show experimentally that roughness can both increase and decrease the adhesive toughness of the contact interface. We show through numerical simulation of continuum adhesive contact models that the contact interface is optimally tough at conditions at which the contact region is at the cusp of the transition through which it turns form being mostly simply connected to being predominantly multiply connected.

Download or read book Analytical Methods In Corrosion Science and Engineering written by Philippe Marcus and published by CRC Press. This book was released on 2005-07-27 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt: Damage from corrosion costs billions of dollars per year. Controlling corrosion requires a fundamental, in-depth understanding of the mechanisms and phenomena involved, and this understanding is best achieved through advanced analytical methods. The first book to treat both surface analytical and electrochemical techniques in a single reference, An

Download or read book Pressure Sensitive Adhesives and Applications written by Istvan Benedek and published by CRC Press. This book was released on 2004-02-03 with total page 678 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pressure-Sensitive Adhesives and Applications, Second Edition explains how pressure-sensitive adhesives (PSAs) work, why they are used, and the technology used to manufacture them. This second edition features the latest developments in the field. Dr. Benedek discusses the factors that affect the rheology and special flow characteristics responsible for the adhesivity of liquid and solid PSAs. His book explores the viscoelastic behavior of PSAs, and compares them to plastics, rubbers, and polymers properties and examines the parameters that influence the conversion process of PSAs from the coating of carrier materials to the properties of the final laminate. The author covers adhesion/cohesion balance, time-temperature dependence of pressure sensitivity, chemical composition, coating properties, and coating processes affect the adhesive properties of PSA and their end products and how application-specific performance indices are used to determine the formulation and manufacture of raw materials. In addition, up-to-date coating machines, converting technology, and environmental considerations in the manufacture of PSA final products as well as industry-specific methods of testing for quality assurance and control are discussed. Pressure-Sensitive Adhesives and Applications, Second Edition combines the theoretical basis of pressure sensitivity with the practical aspects of manufacturing, testing, and use of PSAs. Readers are offered an exhaustive as well as comparative look at the engineering of plastics, adhesives, and pressure-sensitives, resulting in an indispensable, up-to-date reference for adhesive and polymer chemists and technologists.

Download or read book Fundamentals of Adhesion written by L.H. Lee and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Surface Treatment of Materials for Adhesive Bonding written by Sina Ebnesajjad and published by William Andrew. This book was released on 2013-10-22 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aimed at engineers and materials scientists in a wide range of sectors, this book is a unique source of surface preparation principles and techniques for plastics, thermosets, elastomers, ceramics and metals bonding. With emphasis on the practical, it draws together the technical principles of surface science and surface treatments technologies to enable practitioners to improve existing surface preparation processes to improve adhesion and, as a result, enhance product life. This book describes and illustrates the surface preparations and operations that must be applied to a surface before acceptable adhesive bonding is achieved. It is meant to be an exhaustive overview, including more detailed explanation where necessary, in a continuous and logical progression. The book provides a necessary grounding in the science and practice of adhesion, without which adequate surface preparation is impossible. Surface characterization techniques are included, as is an up-to-date assessment of existing surface treatment technologies such as Atmospheric Plasma, Degreasing, Grit blasting, laser ablation and more. Fundamental material considerations are prioritised over specific applications, making this book relevant to all industries using adhesives, such as medical, automotive, aerospace, packaging and electronics. This second edition represents a full and detailed update, with all major developments in the field included and three chapters added to cover ceramic surface treatment, plasma treatment of non-metallic materials, and the effect of additives on surface properties of plastics. A vital resource for improving existing surface treatment processes to increase product life by creating stronger, more durable adhesive bonds Relevant across a variety of industries, including medical, automotive and packaging Provides essential grounding in the science of surface adhesion, and details how this links with the practice of surface treatment

Download or read book Handbook of Adhesion Technology written by Lucas F. M. da Silva and published by Springer. This book was released on 2021-01-14 with total page 1543 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adhesives have been used for thousands of years, but until 100 years ago, the vast majority was from natural products such as bones, skins, fish, milk, and plants. Since about 1900, adhesives based on synthetic polymers have been introduced, and today, there are many industrial uses of adhesives and sealants. It is difficult to imagine a product—in the home, in industry, in transportation, or anywhere else for that matter—that does not use adhesives or sealants in some manner. The Handbook of Adhesion Technology is intended to be the definitive reference in the field of adhesion. Essential information is provided for all those concerned with the adhesion phenomenon. Adhesion is a phenomenon of interest in diverse scientific disciplines and of importance in a wide range of technologies. Therefore, this handbook includes the background science (physics, chemistry and materials science), engineering aspects of adhesion and industry specific applications. It is arranged in a user-friendly format with ten main sections: theory of adhesion, surface treatments, adhesive and sealant materials, testing of adhesive properties, joint design, durability, manufacture, quality control, applications and emerging areas. Each section contains about five chapters written by internationally renowned authors who are authorities in their fields. This book is intended to be a reference for people needing a quick, but authoritative, description of topics in the field of adhesion and the practical use of adhesives and sealants. Scientists and engineers of many different backgrounds who need to have an understanding of various aspects of adhesion technology will find it highly valuable. These will include those working in research or design, as well as others involved with marketing services. Graduate students in materials, processes and manufacturing will also want to consult it.

Download or read book Model Studies of the Effect of Surface Roughness and Mechanical Interlocking on Adhesion written by A. N. Gent and published by . This book was released on 1990 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: The apparent strength of adhesion has been measured for a soft elastic layer adhering to model porous substrates, consisting of rigid plates containing regular arrays of cylindrical holes. Two contributions to the apparent strength have been identified and compared with the preductions of a simple theoretical treatment. The first is adhesion to the surface itself. Because 'rough' surfaces have greater area for bonding, the strength of adhesion was increased by as much as twenty-fold. The second arises from the work of breaking deeply embedded or entangled strands in order to detach the overlayer. Contributions from this mechanism were as much as several hundred times the (low) intrinsic strength of adhesion. Satisfactory agreement was obtained with theory in both cases. Measurements were also made using cloth substrates, when the adhering layer penetrated the cloth completely. The work of detaching and breaking permeating strands was again much larger than the intrinsic strength of adhesion, in reasonable agreement with theoretical predictions. Keywords: Adhesion, Cloth, Elastomers, Fracture, Interlocking, Rubber, Strength, Surface roughness. (sdw).

Download or read book Adhesive Particle Flow written by Jeffery S. Marshall and published by Cambridge University Press. This book was released on 2014-03-31 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is targeted at professionals and graduate students working in disciplines where flow of adhesive particles plays a significant role.

Download or read book Protective Coatings written by Mei Wen and published by Springer. This book was released on 2017-05-26 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on characterization of organic coatings by different testing methods and understanding of structure formation and materials properties. The knowledge of protective organic coatings and current test methods is based largely on empirical experience. This book aims at explaining the coating property changes during film drying and curing in terms of chemical and physical transformations. Current test methods are reviewed with emphasis on understanding their physical basis and expressing the test results in terms of comparable physical quantities. In general, this book provides readers a deeper understanding of the binder design, coating film formation process, properties build-up, appearance and defect formation, and automotive paint application. It also suggests manifold ways to improving the coatings performance. This book is designed for coating professionals to gain deeper understanding of characterization techniques and to select the right ones to solve their coating problems. It is ideal for both experienced and early career scientists and engineers. Also, it is useful for graduate students in the general area of protective coatings.

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.