Download or read book Fabrication and a Study of the Wetting Properties of Nanostructured Surfaces written by and published by . This book was released on 2007 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluid behavior at the microscale exhibits large surface to volume ratios increasing the significance of interfacial phenomena. We have studied two microfluidic phenomena that utilize interplay between microstructure and chemical composition. The first one causes liquid droplets to roll off from surfaces with a very high contact angle. This phenomenon is called superhydrophobic behavior, can be controlled by several tuning parameters. The second one changes the wettability of liquids on a dielectric coated surface with electric potential. The experimental studies were done by first fabricating an ordered array of glass nanocones. Fiber drawing and differential glass etching processes were used to produce cone like structures with lattice constant of 40 [Mu]m down to 1.6 [Mu]m. The superhydrophobic behavior was first studied and modeled in a series of nanocone wafers of increasing aspect ratio from .3 to 15. The characterization was done by the measurement of the contact and rolling angles. The Wenzel to Cassie transition of wetting states was observed. The contact angles were calculated by using the 'axisymmetric drop shape analysis' approach. Next, the study of the electrowetting behavior of two broad categories of structured surfaces was done. One was a low aspect ratio surface exhibiting Wenzel wetting and the other was a high aspect ratio surface exhibiting Cassie wetting. The device for experimental study was prepared by coating additional layers, which included conductive gold and dielectric Parylene-C coatings. Studies were done using silicone oil and air as the ambient medium. Images of drops were taken at different voltages and the contact angles were calculated geometrically. Electrowetting on nanocone arrays was modeled using an energybased approach and the obtained theoretical curves were compared to the experimental ones. Oil helped in achieving a large contact angle change. A qualitative analysis of the electrowetting properties of the surfaces was done based on the voltage-contact angle curves.
Download or read book Wetting and Wettability written by Mahmood Aliofkhazraei and published by BoD – Books on Demand. This book was released on 2015-12-16 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: On the liquid 's surface, the molecules have fewer neighbors in comparison with the bulk volume. As a result, the energy interaction shows itself in the surface tension. Traditionally, the surface tension can be assumed as a force in the unit of the length which can be counted by the unit of Newton on squared meter, or energy on the units of the surface. The surface tension, implies the interface between liquid and vapor, which is an example of the surface tensions. The equilibrium between these surface tensions, decides that a droplet on a solid surface, would have a droplet form or will change to layer form. This book collects new developments in wetting and wettability science.
Download or read book Bio Inspired Wettability Surfaces written by Zheng Yongmei and published by CRC Press. This book was released on 2015-06-16 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: Through natural evolvement in thousands of years, biosurfaces have become highly adaptable to display their biological functions perfectly. Interestingly, they have developed micro-/nanostructures with gradient features to achieve smart wetting controls, such as ultra-hydrophobic water repellency in lotus leaf, directional water collection in wette
Download or read book Fabrication and Characterisation of Nanostructured Surfaces with Extreme Wettabilities written by Nan Gao and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nanotechnologies for Synthetic Super Non wetting Surfaces written by Vincent Senez and published by John Wiley & Sons. This book was released on 2014-08-08 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: Texturing surfaces at micro- and/or nano-scales modifies the interactions of liquids and solids. This book is a summary of the state of the art concerning the development and use of micro/nano-technologies for the design of synthetic liquid repellent surfaces with a particular focus on super-omniphobic materials. It proposes a comprehensive understanding of the physical mechanisms involved in the wetting of these surfaces and reviews emerging applications in various fields such as energy harvesting and biology, as well as highlighting the current limitations and challenges which are yet to be overcome.
Download or read book Nanostructured Thin Films and Surfaces written by and published by John Wiley & Sons. This book was released on 2010-03-08 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book series Nanomaterials for the Life Sciences, provides an in-depth overview of all nanomaterial types and their uses in the life sciences. Each volume is dedicated to a specific material class and covers fundamentals, synthesis and characterization strategies, structure-property relationships and biomedical applications. The series brings nanomaterials to the Life Scientists and life science to the Materials Scientists so that synergies are seen and developed to the fullest. Written by international experts of various facets of this exciting field of research, the series is aimed at scientists of the following disciplines: biology, chemistry, materials science, physics, bioengineering, and medicine, together with cell biology, biomedical engineering, pharmaceutical chemistry, and toxicology, both in academia and fundamental research as well as in pharmaceutical companies. VOLUME 5 - Nanostructured Thin Films and Surfaces
Download or read book Nanostructured Multifunctional Materials for Control of Light Transport and Surface Wettability written by Hyungryul Choi and published by . This book was released on 2014 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biological surfaces have evolved to optimize their structures and physical and chemical properties at the micro/nanoscale for adaptation to different environments, exhibiting a wide variety of beneficial functions, ranging from optical properties to wettability, such as anti-reflection coatings in moth eyes and self-cleaning surfaces of lotus leaves. Combining optical and wetting functions in multifunctional materials is critical for practical engineering applications such as energy harvesting, color generation, and operation of optical instrumentation in humid conditions. However, analyses of the functional design constraints of specified optical and wetting functions followed by integrative optimization have been rare, and limited to simple pairwise combinations from two distinct research disciplines. Furthermore, fabricating the desired multifunctional nanostructured materials remains a difficult engineering challenge due to the limitations of existing nanofabrication methods. The work in this thesis focuses on the joint control of light transport and surface wettability. It starts with analysis and design, followed by implementation of new multifunctional nanostructured materials using novel nanolithographic fabrication techniques. We first consider multifunctional silica surfaces consisting of conical nanostructures (nanocones) for enhanced omnidirectional broadband transmissivity in conjunction with structural superhydrophilicity or robust superhydrophobicity. This is achieved through a systematic approach to concurrent design of nanostructures in both domains and an innovative fabrication procedure that achieves the desired aspect-ratios and periodicities in the nanocones with few defects, high feature repeatability, and large pattern area. Enhanced optical transmissivity exceeding 98% has been achieved over a broad bandwidth and range of incident angles independent of the polarization state. These nanotextured surfaces also demonstrate robust anti-fogging or self-cleaning properties, offering potential benefits for applications such as photovoltaic solar cells. As an extended function of this silica nanocone surface, we propose the systematic design and development of nanostructured transparent anti-fingerprint surface coatings that degrade fingerprint oils using photocatalytic effects. The TiO2-based porous nanoparticle surfaces exhibit short timescales for decomposition of fingerprint oils under ultraviolet light, plus they have transparency comparable to typical glass with low optical haze (
Download or read book Nanostructures Synthesis Functional Properties and Application written by Thomas Tsakalakos and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 694 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Advanced Study Institute on Synthesis, Functional Properties and Applications of Nanostructures, held at the Knossos Royal Village, Heraklion, Crete, Greece, July 26, 2002 - August 4, 2002, successfully reviewed the state-of-the-art of nanostructures and nanotechnology. It was concluded that Nanotechnology is widely agreed to be the research focus that will lead to the next generation of breakthroughs in science and engineering. There are three cornerstones to the expectation that Nanotechnology will yield revolutionary advances in understanding and application: • Breakthroughs in properties that arise from materials fabricated from the nanoscale. • Synergistic behavior that arise from the combination of disparate types of materials (soft vs. hard, organic vs. inorganic, chemical vs. biological vs. solid state) at the nanoscale. • Exploitation of natural (e.g. chemical and biological) assembly mechanisms that can accomplish structural control at the nanoscale. It is expected that this will lead to paradigms for assembling bio-inspired functional systems that accomplish desirable properties that are either unavailable or prohibitively expensive using top-down approaches.
Download or read book Green Tribology written by Michael Nosonovsky and published by Springer Science & Business Media. This book was released on 2012-01-15 with total page 630 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tribology is the study of friction, wear and lubrication. Recently, the concept of “green tribology” as “the science and technology of the tribological aspects of ecological balance and of environmental and biological impacts” was introduced. The field of green tribology includes tribological technology that mimics living nature (biomimetic surfaces) and thus is expected to be environmentally friendly, the control of friction and wear that is of importance for energy conservation and conversion, environmental aspects of lubrication and surface modification techniques, and tribological aspects of green applications such as wind-power turbines or solar panels. This book is the first comprehensive volume on green tribology. The chapters are prepared by leading experts in their fields and cover such topics as biomimetics, environmentally friendly lubrication, tribology of wind turbines and renewable sources of energy, and ecological impact of new technologies of surface treatment.
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 Nanofabrication written by Kamal Prasad and published by CRC Press. This book was released on 2024-09-13 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nature, with its unassuming yet prodigious character, unfolds its assembly and adaptability guided by the principles of thermodynamics and supramolecular chemistry. Every entity in nature, regardless of its form, adheres to these fundamental principles. From individual metabolites to ordinary molecules, each possesses inherent potential for nanomaterial synthesis. This book meticulously compiles diverse green approaches that highlight nature's synthetic prowess and its lavish abundance in nanomaterial synthesis, showcasing potential applications. It unveils the lucrative pathways nature provides for cutting-edge advancements in synthetic methodologies and material applications.
Download or read book Focus on Nanomaterials Research written by B. M. Caruta and published by Nova Publishers. This book was released on 2006 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanotechnology is a 'catch-all' description of activities at the level of atoms and molecules that have applications in the real world. A nanometre is a billionth of a meter, about 1/80,000 of the diameter of a human hair, or 10 times the diameter of a hydrogen atom. Nanotechnology is now used in precision engineering, new materials development as well as in electronics; electromechanical systems as well as mainstream biomedical applications in areas such as gene therapy, drug delivery and novel drug discovery techniques. This book presents the latest research in this frontier field.
Download or read book Polymer Surfaces written by Valente Erasmo Silva and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymer surfaces having micro-nanostructures can be produced using injection molding and hot embossing, high efficiency techniques able to meet the needs of industry for the mass production of polymer parts. Micro-nanosurfaces are in great demand for multiple applications that include antipollution and self-cleaning surfaces, microlenses, dry adhesion surfaces, antireflection coatings, cell culturing and differentiation as well as superhydrophobic surfaces. Polymer Surfaces: Fabrication, Modification and Applications discusses the injection molding of micro-nanostructured polymer surfaces consists of three main technical steps: mold inserts, processing parameters and demolding. The authors also discuss the capabilities of various demolding methods, such as antistiction coatings, to protect and enhance the surface properties of micro-nanostructures. The subsequent contribution focuses on biocompatible and biodegradable hollow nanoparticles prepared via the layer-by-layer deposition of polymer thin films on sacrificial templates. The review encompasses all aspects of nanocapsules from preparation through characterization and the applications as drug carriers. A promising strategy is proposed for facilely and successively replicating randomly arranged pyramids on an etched silicon wafer to polystyrene surface. The authors propose that this fast and efficient replication strategy could be an excellent candidate for developing antireflective protective layers without complicated procedures and expensive materials. A promising strategy was proposed for facilely and successively replicating the natural functional nanostructure of the cicada wing onto polystyrene surfaces in the concluding study. This work may direct the design of gradient wetting surfaces by mimicking the nanopillar structure of cicada wing. This strategy could aid in mimicking bio-inspired functional micro/nanostructures without complicated procedures and expensive materials.
Download or read book Condensation and Wetting Dynamics on Micro Nano Structured Surfaces written by Emre Olceroglu and published by . This book was released on 2017 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: Because of their adjustable wetting characteristics, micro/nanostructured surfaces are attractive for the enhancement of phase-change heat transfer where liquid-solid-vapor interactions are important. Condensation, evaporation, and boiling processes are traditionally used in a variety of applications including water harvesting, desalination, industrial power generation, HVAC, and thermal management systems. Although they have been studied by numerous researchers, there is currently a lack of understanding of the underlying mechanisms by which structured surfaces improve heat transfer during phase-change. This PhD dissertation focuses on condensation onto engineered surfaces including fabrication aspect, the physics of phase-change, and the operational limitations of engineered surfaces. While superhydrophobic condensation has been shown to produce high heat transfer rates, several critical issues remain in the field. These include surface manufacturability, heat transfer coefficient measurement limitations at low heat fluxes, failure due to surface flooding at high supersaturations, insufficient modeling of droplet growth rates, and the inherent issues associated with maintenance of non-wetted surface structures. Each of these issues is investigated in this thesis, leading to several contributions to the field of condensation on engineered surfaces. A variety of engineered surfaces have been fabricated and characterized, including nanostructured and hierarchically-structured superhydrophobic surfaces. The Tobacco mosaic virus (TMV) is used here as a biological template for the fabrication of nickel nanostructures, which are subsequently functionalized to achieve superhydrophobicity. This technique is simple and sustainable, and requires no applied heat or external power, thus making it easily extendable to a variety of common heat transfer materials and complex geometries. To measure heat transfer rates during superhydrophobic condensation in the presence of non-condensable gases (NCGs), a novel characterization technique has been developed based on image tracking of droplet growth rates. The full-field dynamic characterization of superhydrophobic surfaces during condensation has been achieved using high-speed microscopy coupled with image-processing algorithms. This method is able to resolve heat fluxes as low as 20 W/m2 and heat transfer coefficients of up to 1000 kW/m2, across an array of 1000's of microscale droplets simultaneously. Nanostructured surfaces with mixed wettability have been used to demonstrate delayed flooding during superhydrophobic condensation. These surfaces have been optimized and characterized using optical and electron microscopy, leading to the observation of self-organizing microscale droplets. The self-organization of small droplets effectively delays the onset of surface flooding, allowing the superhydrophobic surfaces to operate at higher supersaturations. Additionally, hierarchical surfaces have been fabricated and characterized showing enhanced droplet growth rates as compared to existing models. This enhancement has been shown to be derived from the presence of small feeder droplets nucleating within the microscale unit cells of the hierarchical surfaces. Based on the experimental observations, a mechanistic model for growth rates has been developed for superhydrophobic hierarchical surfaces. While superhydrophobic surfaces exhibit high heat transfer rates they are inherently unstable due to the necessity to maintain a non-wetted state in a condensing environment. As an alternative condensation surface, a novel design is introduced here using ambiphilic structures to promote the formation of a thin continuous liquid film across the surface which can still provide the benefits of superhydrophobic condensation. Preliminary results show that the ambiphilic structures restrain the film thickness, thus maintaining a low thermal resistance while simultaneously maximizing the liquid-vapor interface available for condensation.
Download or read book Controlling the Wetting Behaviors of Copper Nanostructures Through Solution Immersion Method written by Pranav P. Dubey and published by . This book was released on 2017 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: Addressing a desired surface wettability has been a significant challenge for a variety of innovative thermofluidic applications from anti-icing coating to two-phase heat exchangers. Surface wettability can be controlled by fabricating nanostructures on the surfaces and modifying their chemistry. While numerous nanofabrication efforts have been investigated for this purpose, a solution immersion method is suggested in this research since it can effectively install nanostructures on two-dimensional or three-dimensional surfaces over a large area. Therefore, we employ the solution immersion method in order to investigate the wettability of copper oxide nanostructures related to fabrication parameters. The examples of copper oxide nanostructures include nanoneedles and nanoflowers/nanograsses on polished copper substrates and open-cell porous copper structures (i.e. copper inverse opals). Detailed analysis is followed to quantify surface structural details, chemical composition, and surface wettability. The understanding of structure- and chemistry-dependent wettability will pave the way for the implementation of copper nanostructures with well-controlled wetting properties into future copper-based thermofluidic applications such as heat exchangers and heat pipes.
Download or read book Advanced Research in Nanosciences for Water Technology written by Ram Prasad and published by Springer. This book was released on 2019-02-04 with total page 461 pages. Available in PDF, EPUB and Kindle. Book excerpt: The establishment of clean, safe water is one of the major challenges facing societies around the globe. The continued urbanization of human populations, the increasing manipulation of natural resources, and the resulting pollution are driving remarkable burden on water resources. Increasing demands for food, energy, and natural resources are expected to continue to accelerate in the near future in response to the demands of these changing human populations. In addition, the complexity of human activities is leading to a diversity of new chemical contaminants in the environment that represent a major concern for water managers. This will create increased pressure on both water quantity and quality, making it increasingly difficult to provide a sustainable supply of water for human welfare and activities. Although protection of water resources is the best long-term solution, we will also need innovative novel approaches and technologies to water treatment to ensure an adequate superior quality resource to meet these needs. Solving tomorrow’s water issues will require unique approaches that incorporate emerging new technologies. Great advances have been made in the area of nanotechnology. Due to their unique physical and chemical properties, nanomaterials are extensively used in antibacterial medical products, membrane filters, electronics, catalysts, and biosensors. Nanoparticles can have distinctly different properties from their bulk counterparts, creating the opportunity for new materials with a diversity of applications. Recent developments related to water treatment include the potential use of carbon nanotubes, nanocompositae, nanospheres, nanofibers, and nanowires for the removal of a diversity of chemical pollutants. By exploiting the assets and structure of these new materials, such as increased surface area, high reactivity, and photocatalytic action, it will be possible to create technologies that can be very efficient at removing and degrading environmental pollutants. Understanding and using these unique properties should lead to innovative, cost-effective applications for addressing the complexities of emerging needs for water treatment and protection. Although still in the early stages, research into the application of nanotechnology shows great promise for solving some of these major global water issues. This comprehensive text describes the latest research and application methods in this rapidly advancing field.
Download or read book Heat Exchangers written by Laura Castro Gómez and published by BoD – Books on Demand. This book was released on 2022-03-23 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: The demand for energy to satisfy the basic needs and services of the population worldwide is increasing as are the economic costs associated with energy production. As such, it is essential to emphasize energy recovery systems to improve heat transfer in thermal processes. Currently, significant research efforts are being conducted to expose criteria and analysis techniques for the design of heat exchange equipment. This book discusses optimization of heat exchangers, heat transfer in novel working fluids, and the experimental and numerical analysis of heat transfer applications.
