Finite element analysis of single cell stiffness measurement using PZT-integrated buckling nanoneedle

In this project, we propose a new technique for real-time single cell stiffness measurement using PZT-integrated buckling nanoneedle. The PZT and the buckling part of the nanoneedle have been modelled and validated using ABAQUS software. The two parts are integrated together to function as single unit. After calibration, the stiffness, Young’s modulus, Poisson’s ratio and sensitivity of the PZT-integrated buckling nanoneedle have been determined to be 0.8600 Nm-1, 123.4700 GPa, 0.3000 and 0.0693 VmN-1 respectively. Three Saccharomyces cerevisiae yeast cells have been modelled using ABAQUS and validated based on compression test. We determine the average global stiffness and Young’s modulus of the cells to be 10.8867 ± 0.0094 Nm-1 and 110.7033 ± 0.0081 MPa respectively. The nanoneedle and the cell have been assembled to measure the local stiffness of the single Saccharomyces cerevisiae yeast cell. An indentation force of 0.2 μN equivalent to single mode eigenvalue which causes the nanoneedle to buckle has been applied along y-axis. The local stiffness, Young’s modulus and PZT output voltage of three different sizes Saccharomyces cerevisiae yeast cells have been determined at different environmental conditions. We investigated that, at low temperature the stiffness value is low to adapt to the change in the environmental condition as a result the cell is vulnerable to virus and bacteria attack. In future, the technique will supplement the present-day biochemical technique for diseases diagnosis

Cutting Edge Nanotechnology

The main purpose of this book is to describe important issues in various types of devices ranging from conventional transistors (opening chapters of the book) to molecular electronic devices whose fabrication and operation is discussed in the last few chapters of the book. As such, this book can serve as a guide for identifications of important areas of research in micro, nano and molecular electronics. We deeply acknowledge valuable contributions that each of the authors made in writing these excellent chapters

Zinc Oxide Nanostructures: Synthesis and Characterization

The summary should be ca. 200 words; this text will present the book in all promotional forms (e.g. flyers). Please describe the book in straightforward and consumer-friendly terms. [Zinc oxide (ZnO) is a wide band gap semiconductor with an energy gap of 3.37 eV at room temperature. It has been used considerably for its catalytic, electrical, optoelectronic, and photochemical properties. ZnO nanomaterials, such as quantum dots, nanorods, and nanowires, have been intensively investigated for their important properties. Many methods have been described in the literature for the production of ZnO nanostructures, such as laser ablation, hydrothermal methods, electrochemical deposition, sol-gel methods, chemical vapour deposition, molecular beam epitaxy, the common thermal evaporation method, and the soft chemical solution method. The present Special Issue is devoted to the synthesis and characterization of ZnO nanostructures with novel technological applications.

Development and characterisation of multifunctional one-dimensional fibres reinforced composite coatings

Nanocomposite coatings are attractive due to their unique mechanical, physical and multifunctional properties, which can address the limitations of conventional monolithic structures to achieve an excellent combination of strength, stiffness, toughness, and some other functional properties. In this study, a novel in-situ low temperature (below 500ºC) hybrid plasma technology combining active-screen plasma co-sputtering and PECVD has been developed to cost-effectively generate vertically aligned carbon nanotubes (VACNTs) films. A two-step approach has been employed to develop VACNTs reinforced composite coatings. A well-designed CNTs reinforced diamond-like carbon (DLC) composite coating can be formed using the PECVD. Besides, the Ag wires reinforced composite coatings have been deposited through a one-step approach using the advanced hybrid plasma technology combining ASP co-sputtering and plasma carburising in a plasma ambient of CH4 (1.5%) and H2 (98.5%). SEM, TEM, XRD, XPS have been applied to characterise the morphologies and microstructures of these novel composite coatings

Growth and characterization of ZnO and SiC nanowires

The synthesis of semiconductor nanowires has been studied intensively worldwide for a wide spectrum of materials. Such low-dimensional nanostructures are not only interesting for fundamental research due to their unique structural and physical properties relative to their bulk counterparts, but also offer fascinating potential for future technological applications. Deeper understanding and sufficient control of the growth of nanowires are central to the current research interest. The objective of the thesis work is synthesizing semiconductor nanowires using various growth processes, with a focus on the spontaneous growth process, which offers an opportunity for the control of spatial positioning of nanowires. Zinc oxide (ZnO) based and Silicon carbide (SiC) based nanowires have been concentrated to synthesize using vapor-solid (VS) and vapor–liquid–solid (VLS) techniques respectively. ZnO is one of very interesting semiconductor material because of its physical and chemical properties. Also, it is well known that high n-type conductivity can be achieved by alloying zinc oxide with group III elements (such as Al, In or Ga) in ternary or even quaternary oxide compounds, in order to obtain transparent conducting oxides (TCOs). In this part of work, there were two major materials have been synthesized such as vertically aligned ZnO nanorods and ternary Zn(In,Ga,Sn)O nanorods using vapor phase technique. First, solution-free and catalyst-free vertically aligned ZnO nanorods have been synthesized by thermal CVD reactor at relatively low temperature (< 500 °C) to produce high-surface 3D photoanode on glass substrate. Different TCOs films such as Al doped ZnO films deposited by PED, RF-sputtering techniques and ITO were considered for the growth as starting seeding layer for the nanorods. The aim of this work is mainly focused to control the thickness and length of these nanostructures by varying not only the growth parameters, such as amount of Zn evaporation, but also substrate characteristics, such as grain size of Al doped ZnO and ITO seeding films. Second, Indium Zinc oxide nanorods (IZO-NRs) have been obtained at temperatures lower than 500°C using same CVD system, with a resulting indium concentration larger than 1%. The growth of these ternary oxide nanostructures has been obtained at relatively low temperature, starting from the corresponding metals, thanks to the direct deposition on the growth substrate of an In layer, which in its molten state and upon mixture with Zn acts as growth seed. The obtained indium concentration corresponds to the value required to get metallic behavior and make this ternary oxide a TCO (transparent conducting oxide), while the used temperature range makes it compatible also with commercial glass substrates. Same technique have been used to obtain GaZnO and SnZnO nanostructures. Among many kind of semiconductor, SiC is an important wide band gap IV-IV semiconducting material and it exhibit excellent, unique physical and mechanical properties at nano-scale, which lead to their potential applications for being used as the building blocks in nanoelectronics and nanooptoelectronics. Also, it has biocompatibility and inertness can be exploited for biomedical applications. In this part of work, there were two types of SiC nanowires have been synthesized using VLS growth technique. First, Cubic SiC nanowires were successfully grown using home-made induction heated Vapor Phase Epitaxy (VPE) reactor on Si (100) and Si (111) substrate using nickel (Ni) and Iron (Fe) as a catalysts. The main aim of this work is to optimize the condition to grow SiC nanowires with Ni and Fe catalyst. The size and shape of the nanowires has been controlled using temperature and gas flow rate. Second, self-assembled SiC core with SiO2 shell coaxial nanowires using Ni and Fe catalyst have been synthesized by thermal CVD reactor. The growth conditions were optimized for both catalyst using temperature, gas flow rate. This SiC /SiO2 coaxial core/shell nanowires (NWs) are intriguing as novel nanostructured to be functionalized because of the 3C-SiC biocompatibility and of the presence of a SiO2 native shell that favours surface functionalization. Those findings are encouraging in the prospective to employ this functionalized system for different nano-medical applications such as targeted therapy against deep tumor cells

Carbon Nanotubes

Since their discovery in 1991, carbon nanotubes have been considered as one of the most promising materials for a wide range of applications, in virtue of their outstanding properties. During the last two decades, both single-walled and multi-walled CNTs probably represented the hottest research topic concerning materials science, equally from a fundamental and from an applicative point of view. There is a prevailing opinion among the research community that CNTs are now ready for application in everyday world. This book provides an (obviously not exhaustive) overview on some of the amazing possible applications of CNT-based materials in the near future

Investigations of Surface-Tension Effects Due to Small-Scale Complex Boundaries

The earliest man-made irrigation systems in recorded history date back to the ancient Egypt and Mesopotamia era. After thousands of years of experience, exploration, and experimenting, mankind have learned how to construct canals and dams and use pipes and pumps to direct and control water flow, but till this day, there are still some behaviors of water and other simple fluids that surprise us. One such example is the lotus effect: a surface-tension effect which allows raindrops to roll freely on a lotus leaf as if they were drops of mercury. One of the key factors that determine how a fluid system behave is the size-scale. Fluids flow at small scales very differently than they do at large scales. The standard comparing to which small and large are defined is the capillary length. A number of surface-tension related phenomena are unfamiliar because they are only noticeable at length-scales of a few millimeters or below, and they look nothing like what we would expect fluids to behave when dominated by gravity. As fascinating as many of them may seem at first glance, surface-tension phenomena are actually not that far away from our daily lives. Surface tension is everywhere because it costs energy to create areas of surfaces and interfaces, just like it costs energy to deform a solid (resulting in elasticity) or to elevate a weight (resulting in gravity). To minimize energy, a surface or an interface has the tendency to contract, and this tendency generates surface tension. The size of a system significantly affects the relative strengths of surface-tension effects comparing to effects of body forces, most commonly gravity. By equating the estimated magnitudes of surface tension and gravitational forces of a system, a length scale, know as the capillary length, can be defined. The capillary length of water on earth is about 2.7 mm. At the length scale of everyday objects, which is usually above the capillary length, surface-tension effects are not always prominent, because at those scales the competing force, gravity, is often much stronger. That is why the surface of a glass of water is more or less flat. However, as the size-scale decreases, surface tension decreases a lot slower than gravity, so when the size of a fluid system gets down to below the capillary length, surface tension takes over. One of the defining characteristics of this moment in human history, is the tremendous efforts we are putting into the research and engineering of micro- and nano-scale materials and structures − systems where surface tension is often the predominant force. It is important to study surface-tension effects so that we can use them to our advantage. In this Ph.D. dissertation, we have investigated some important surface-tension phenomena including capillarity, wetting, and wicking. We mainly focus on the geometric aspects of these problems, and to learn about how structures affect properties. Understanding these phenomena can help develop fabrication methods (Chapter 2), study surface properties (Chapter 3), and design useful devices (Chapter 4) at scales below the capillary length. In the first project (Chapter 2), we used numerical simulations and experiments to study the meniscus of a fluid confined in capillaries with complicated cross-sectional geometries. In the simulations, we computed the three-dimensional shapes of the menisci formed in polygonal and star-shaped capillaries with sharp or rounded corners. Height variations across the menisci were used to quantify the effect of surface tension. Analytical solutions were derived for all the cases where the cross-sectional geometry was a regular polygon or a regular star-shape. Power indices that characterize the effects of corner rounding were extracted from simulation results. These findings can serve as guide for fabrications of unconventional three-dimensional structures in Capillary Force Lithography experiments [J. Feng (2011) (a)]. Experimental demonstrations of the working principle was also performed. Although quantitative matching between simulation and experimental results was not achieved due to the limitation of material properties, clear qualitative trends were observed and interesting three-dimensional nano-structures were produced. A second project (Chapter 3) focused on developing techniques to produce three-dimensional hierarchically structured superhydrophobic surfaces with high aspect ratios. We experimented with two different high-throughput electron-beam-lithography processes featuring single and dual electron-beam exposures. After a surface modification procedure with a hydrophobic silane, the structured surfaces exhibited two distinct superhydrophobic behaviors − high and low adhesion. While both types of superhydrophobic surfaces exhibited very high (approximately 160_) water advancing contact angles, the water receding contact angles on these two different types of surfaces differed by about 50_ _ 60_, with the low-adhesion surfaces at about 120_ _ 130_ and the high-adhesion surfaces at about 70_ _ 80_. Characterizations of both the microscopic structures and macroscopic wetting properties of these product surfaces allowed us to pinpoint the structural features responsible for specific wetting properties. It is found that the advancing contact angle was mainly determined by the primary structures while the receding contact angle is largely affected by the side-wall slope of the secondary features. This study established a platform for further exploration of the structure aspects of surface wettability [J. Feng (2011) (b)]. In the third and final project (Chapter 4), we demonstrated a new type of microfluidic channel that enable asymmetric wicking of wetting fluids based on structure-induced direction-dependent surface-tension effect. By decorating the side-walls of open microfluidic channels with tilted fins, we were able to experimentally demonstrate preferential wicking behaviors of various IPA-water mixtures with a range of contact angles in these channels. A simplified 2D model was established to explain the wicking asymmetry, and a complete 3D model was developed to provide more accurate quantitative predictions. The design principles developed in this study provide an additional scheme for controlling the spreading of fluids [J. Feng (2012)]. The research presented in this dissertation spreads out across a wide range of physical phenomena (wicking, wetting, and capillarity), and involves a number of computational and experimental techniques, yet all of these projects are intrinsically united under a common theme: we want to better understand how simple fluids respond to small-scale complex surface structures as manifestations of surface-tension effects. We hope our findings can serve as building blocks for a larger scale endeavor of scientific research and engineering development. After all, the pursue of knowledge is most meaningful if the results improve the well-being of the society and the advancement of humanity

Converting Inorganic Rust to Organic Nanostructured Conducting Polymers: Synthesis and Applications

Iron rust is a type of corrosion product, coming from the chemical reaction between iron and oxygen in the presence of water that first documented ca. 800 BCE. It is a heterogeneous inorganic solid-state material composed of multiple phases and is ubiquitous throughout the universe. Rust species such as Hematite (α-Fe2O3), Akaganeite (β-FeOOH), and ferrous hydroxide (Fe(OH)2), make up the solid-state chemical family composed of iron oxides, oxyhydroxides, and hydroxides that are typically recognized as chemical waste. Conducting polymer is a type of organic plastic composed of long chains with repeating subunits that bonding with strong interactions between neighboring molecules. Unlike conventional insulating plastics, conducting polymers possess a unique molecular structure with an electronically conjugated backbone, enabling electron freely to travel interchain and intrachain, and such subject received the Nobel Prize in Chemistry in 2000. This work introduces a unique synthetic strategy that advances the state-of-the-art chemical synthesis of nanostructured conducting polymers by utilizing “waste” material rust, named rust-based vapor-phase polymerization (RVPP). The unique conversion between inorganic rust and organic conducting polymer leads to controlled depositions of poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy) nanostructures, including fibers, rods, flakes, and thin films. Owing to the high conductivity, large surface area, and tunable band gap, nanostructured conducting polymers provide promising applications in energy storage, photovoltaics, sensing, CO2 photoreduction, and antimicrobial field