Author: Dietrich Alexander Dehlinger Publisher: ISBN: Category : Languages : en Pages : 180
Book Description
It is traditionally difficult to integrate a wide range of nanocomponents into macroscopic or mesoscopic scale systems. Traditional methods of nanofabrication use large scale patterning of homogenous layers, or make use of the intrinsic properties of the particles in to bind them together in an uncontrolled fashion. In this dissertation, a method for the rapid, highly controlled deposition of water soluble nanoparticles is demonstrated. Through the use of direct current controlled electrodes in a buffered solution, nanoparticles are pulled from a dilute solution to a complementary binding surface in a few seconds where they form a single layer. By repeated processing steps we are able to rapidly fabricate multilayered structures using different nanoparticles, making use of both overall directed assembly and the local self assembly of the particles themselves. Because we are able to control the particle concentration, we can effectively control the particle binding rate at the deposition surface. Described in detail is a method for characterizing the deposition process to determine both the optimal parameters (in terms of deposition time and current) for a given particle type, and methods to determine the level of interparticle self binding. Optical fluorescent imaging and electron microscopy were used extensively to characterize the rate of particle accumulation both as a function of current and time for a single deposition, and for the overall process through subsequent layers. The electric field assisted self assembly work was carried out for 40nm and 200nm biotin/streptavidin coated particles, as well as particles covered in various DNA sequences, quantum dots, and gold particles. Particle deposition profiles across the electrode are also discussed, with the root causes for the observed pattern explained using various electric field deposition from this work, as well as some supporting experiments from tangentially related experiments. These experimental results are compared to various simulated systems. Finally some preliminary work on long range, high voltage, high conductivity dielectrophoresis systems is discussed with an eye towards fully integrated sample analysis systems.
Author: Manish Mittal Publisher: ISBN: 9781124241135 Category : Anisotropy Languages : en Pages :
Book Description
In this thesis we demonstrate the use of external fields to direct the self assembly of anisotropic particles into controlled microstructure. Directed self-assembly by external electric field has the advantage that it leads to rapid assembly of particles, it is reversible and the interactions can be tuned by controlling the field parameters. However, the polarization mechanism of colloidal particles and its dependence on the properties of the particle and the medium is not well understood. We use optical tweezers to measure the interactions between particles as a function of medium salt concentration and field frequency. We identify the double layer relaxation as the dominant polarization mechanism. This enables us to reinterpret the order-disorder phase diagram, published earlier by Lumsdon and co-workers, and thus predict the electric field required to assemble particles given the size of the particles, the frequency of the field and the type and concentration of the counter-ion in the system. We study the application of external field to anisotropic nanoparticle assembly using zeolite particles. The assembly of disk-shaped zeolite particles is interesting from the perspective of both understanding how anisotropic particles respond in electric field and also to self-assemble a zeolite structure, a material with large number of industrial applications. Similar to spherical particles, the disk shaped particles also form a hexagonal close-packed structure by assembling in a side-to-side fashion with their long axis, the diameter, oriented along the field direction. However, due to the smaller size of particles the field strengths required to assemble these particles are higher than those used in interaction measurements. At high field strengths the particles also form a brush-like structure that grows from the electrode interface towards the bulk suspension. The assembly of particles near the electrode interface occurs due to an interplay between dipolar force and the drag force due to electro-hydrodynamic (EH) flow. In addition to generalizing the dipolar interaction mechanism to anisotropic particles, this work also demonstrates the challenges associated with the use of only electric field to self-assemble particles into a permanent structure. To form an irreversible structure under electric field we develop a combined field and flow directed technique for assembling anisotropic particles and show its application using ellipsoidal titanium dioxide nanoparticles. The colloidal suspension of titanium dioxide particles, confined between glass substrates, is allowed to dry in the presence of electric field. The electric field orients the particles and due to the evaporation of solvent micrometer thick particulate films deposit onto the glass substrate. The microstructure of the film is controlled by tuning the field strength and the field frequency. On varying the field frequency the particles undergo a parallel-random-perpendicular orientation transition with respect to the electric field direction. The optical and the mechanical properties of the film are dependent on the orientation of the deposited particles. This work demonstrates a novel method of assembling anisotropic particles using external fields and controlling the microstructure using field frequency. Although field-assisted convective deposition allows us to control the orientation of the particles, the thickness of the film cannot be precisely controlled and the electrode gap limits the area of the assembled region. Unlike external electric fields, flow fields are more scalable and could be used to deposit particles over a large area. We use a flow coating technique to deposit ellipsoidal titanium dioxide particles on a glass substrate. The film is deposited from a colloidal suspension confined between a fixed blade and a translating substrate. Both the microstructure and the thickness of the film are simultaneously controlled by varying the particle volume fraction in the suspension, the velocity of the substrate and the angle between the blade and the substrate. At volume fractions above the isotropic-nematic transition the particles in the film orient along the coating direction. At volume fractions below the isotropic-nematic transition the particles do not orient along the coating direction. The substrate velocity and the blade angle affect the shear and extensional stresses exerted on the colloidal particles, which determine the orientation of the particles in the deposited film. Thus, flow coating is a rapid and scalable approach for de- positing thin films of nanostructured material consisting of anisotropic particles. (Abstract shortened by UMI.).
Author: Rongchao Jin Publisher: John Wiley & Sons ISBN: 1119788641 Category : Technology & Engineering Languages : en Pages : 533
Book Description
Explore recent progress and developments in atomically precise nanochemistry Chemists have long been motivated to create atomically precise nanoclusters, not only for addressing some fundamental issues that were not possible to tackle with imprecise nanoparticles, but also to provide new opportunities for applications such as catalysis, optics, and biomedicine. In Atomically Precise Nanochemistry, a team of distinguished researchers delivers a state-of-the-art reference for researchers and industry professionals working in the fields of nanoscience and cluster science, in disciplines ranging from chemistry to physics, biology, materials science, and engineering. A variety of different nanoclusters are covered, including metal nanoclusters, semiconductor nanoclusters, metal-oxo systems, large-sized organometallic nano-architectures, carbon clusters, and supramolecular architectures. The book contains not only experimental contributions, but also theoretical insights into the atomic and electronic structures, as well as the catalytic mechanisms. The authors explore synthesis, structure, geometry, bonding, and applications of each type of nanocluster. Perfect for researchers working in nanoscience, nanotechnology, and materials chemistry, Atomically Precise Nanochemistry will also benefit industry professionals in these sectors seeking a practical and up-to-date resource.
Author: Sivaraman Ramaswamy Publisher: ISBN: Category : Languages : en Pages : 117
Book Description
Self-assembled nanoscale structures are the basis for various technological advancements in functional materials, sensors, and molecular circuits and factories. With significant progress in self-assembly of periodic nanostructures (such as monolayers), the focus is now shifting towards non-periodic structures. Control of various interaction force fields (electrostatic, Van der Waals, etc.) between the nanoparticles and external controls can result in the formation of nanostructures with desired geometry. The aim is to design the nanoparticles and the external actuators such that the desired structure can be self-assembled rapidly with high reliability and avoiding any kinetic trapping that an ill-designed energy landscape might cause. Deterministic dynamic modeling of such self-assembled nanostructures, directed by external fields, through a Master Equation approach, leads to a set of differential equations of such large size that even the most efficient solution algorithms are overwhelmed. Thus, model reduction is a key necessity. This thesis presents a methodological approach and specific algorithms, which generate time-varying, reduced-order models for the description of directed self-assembly of nanoparticles by external fields. The approach is based on Finite State Projection and is adaptive, i.e., it generates reduced-order models that vary over time. The algorithm uses event-detection concepts to determine automatically, during simulation, suitable time points at which the projection space and thus the structure of the reduced-order model change, in such a way that the computational load remains low while the upper bound on the simulation error, resulting from model reduction, is lower than a prescribed maximum limit. The thesis also presents an optimal control strategy that can guide any initial random configuration of nanoparticles to a final structure of desired geometry, in minimum time. It employs a multi-resolution view of the dynamically evolving configurations of nanoparticles, which are described through the simulation methodology described before. External charges, attracting or repelling the nanoparticles, are the controls, whose location and intensity are determined by the optimality conditions of the optimal control strategy. To ensure analytic consistency of the parametric sensitivities, during the computation of the optimal controls, and thus guarantee the optimality of the resulting control policy, a priori determination of enlarged constant projection spaces is shown to be essential. The thesis also presents a series of case studies, which illustrate how the proposed methods can be used to simulate effectively directed self-assembly of an appreciable number of nanoparticles, and reach the desired geometry. These case studies also illuminate several of its features, such as: superiority over a static optimal solution; evasion of kinetic traps; and effective handling of combinatorial complications arising for systems with large-size domains and many particles.
Author: Shu Chien Publisher: World Scientific Publishing Company ISBN: 9813101547 Category : Science Languages : en Pages : 563
Book Description
This bestselling textbook will introduce undergraduate bioengineering students to the fundamental concepts and techniques, with the basic theme of integrative bioengineering. It covers bioengineering of several body systems, organs, tissues, and cells, integrating physiology at these levels with engineering concepts and approaches; novel developments in tissue engineering, regenerative medicine, nanoscience and nanotechnology; state-of-the-art knowledge in systems biology and bioinformatics; and socio-economic aspects of bioengineering.One of the distinctive features of the book is that it is integrative in nature (integration of biology, medicine and engineering, across different levels of the biological hierarchy, and basic knowledge with applications). It is unique in that it covers fundamental aspects of bioengineering, cutting-edge frontiers, and practical applications, as well as perspectives of bioengineering development. Furthermore, it covers important socio-economical aspects of bioengineering such as ethics and entrepreneurism.
Author: Shafigh Mehraeen Publisher: BoD – Books on Demand ISBN: 1789239605 Category : Technology & Engineering Languages : en Pages : 102
Book Description
Top-down approaches are currently the main contributor of fabricating microelectronic devices. However, the prohibitive cost of numerous technological steps in these approaches is the main obstacle to further progress. Furthermore, a large number of applications necessitate fabrication of complex and ultra-small devices that cannot be made using these approaches. New approaches based on natural self-assembly of matter need to be developed to allow for fabrication of micro and nanoelectronic devices. Self-assembly of nanostructures is a dynamic field, which explores physics of these structures and new ways to fabricate them. However, the major problem is how to control the properties of the nanostructures resulting from low dimensionality. This book presents recent advances made to address this problem, and fabricate nanostructures using self-assembly.
Author: Katsuhiko Ariga Publisher: Elsevier ISBN: 0323994733 Category : Technology & Engineering Languages : en Pages : 648
Book Description
Materials Nanoarchitectonics: From Integrated Molecular Systems to Advanced Devices provides the latest information on the design and molecular manipulation of self-organized hierarchically structured systems using tailor-made nanoscale materials as structural and functional units. The book is organized into three main sections that focus on molecular design of building blocks and hybrid materials, formation of nanostructures, and applications and devices. Bringing together emerging materials, synthetic aspects, nanostructure strategies, and applications, the book aims to support further progress, by offering different perspectives and a strong interdisciplinary approach to this rapidly growing area of innovation. This is an extremely valuable resource for researchers, advanced students, and scientists in industry, with an interest in nanoarchitectonics, nanostructures, and nanomaterials, or across the areas of nanotechnology, chemistry, surface science, polymer science, electrical engineering, physics, chemical engineering, and materials science. Offers a nanoarchitectonic perspective on emerging fields, such as metal-organic frameworks, porous polymer materials, or biomimetic nanostructures Discusses different approaches to utilizing "soft chemistry" as a source for hierarchically organized materials Offers an interdisciplinary approach to the design and construction of integrated chemical nano systems Discusses novel approaches towards the creation of complex multiscale architectures
Author: Ramanathan Nagarajan Publisher: John Wiley & Sons ISBN: 1119001366 Category : Science Languages : en Pages : 364
Book Description
An introduction to the state-of-the-art of the diverse self-assembly systems Self-Assembly: From Surfactants to Nanoparticles provides an effective entry for new researchers into this exciting field while also giving the state of the art assessment of the diverse self-assembling systems for those already engaged in this research. Over the last twenty years, self-assembly has emerged as a distinct science/technology field, going well beyond the classical surfactant and block copolymer molecules, and encompassing much larger and complex molecular, biomolecular and nanoparticle systems. Within its ten chapters, each contributed by pioneers of the respective research topics, the book: Discusses the fundamental physical chemical principles that govern the formation and properties of self-assembled systems Describes important experimental techniques to characterize the properties of self-assembled systems, particularly the nature of molecular organization and structure at the nano, meso or micro scales. Provides the first exhaustive accounting of self-assembly derived from various kinds of biomolecules including peptides, DNA and proteins. Outlines methods of synthesis and functionalization of self-assembled nanoparticles and the further self-assembly of the nanoparticles into one, two or three dimensional materials. Explores numerous potential applications of self-assembled structures including nanomedicine applications of drug delivery, imaging, molecular diagnostics and theranostics, and design of materials to specification such as smart responsive materials and self-healing materials. Highlights the unifying as well as contrasting features of self-assembly, as we move from surfactant molecules to nanoparticles. Written for students and academic and industrial scientists and engineers, by pioneers of the research field, Self-Assembly: From Surfactants to Nanoparticles is a comprehensive resource on diverse self-assembly systems, that is simultaneously introductory as well as the state of the art.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
Directed self-assembly promises to be the technologically and economically optimal approach to industrial-scale nanotechnology, and will enable the realization of inexpensive, reproducible and active nanostructured materials with tailored photonic, transport and mechanical properties. These new nanomaterials will play a critical role in meeting the 21st century grand challenges of the US, including energy diversity and sustainability, national security and economic competitiveness. The goal of this work was to develop and fundamentally validate methods of directed selfassembly of nanomaterials and nanodispersion processing. The specific aims were: 1. Nanocolloid self-assembly and interactions in AC electric fields. In an effort to reduce the particle sizes used in AC electric field self-assembly to lengthscales, we propose detailed characterizations of field-driven structures and studies of the fundamental underlying particle interactions. We will utilize microscopy and light scattering to assess order-disorder transitions and self-assembled structures under a variety of field and physicochemical conditions. Optical trapping will be used to measure particle interactions. These experiments will be synergetic with calculations of the particle polarizability, enabling us to both validate interactions and predict the order-disorder transition for nanocolloids. 2. Assembly of anisotropic nanocolloids. Particle shape has profound effects on structure and flow behavior of dispersions, and greatly complicates their processing and self-assembly. The methods developed to study the self-assembled structures and underlying particle interactions for dispersions of isotropic nanocolloids will be extended to systems composed of anisotropic particles. This report reviews several key advances that have been made during this project, including, (1) advances in the measurement of particle polarization mechanisms underlying field-directed self-assembly, and (2) progress in the directed self-assembly of anisotropic nanoparticles and their unique physical properties.
Author: Jason Kee Yang Ong Publisher: ISBN: 9781321081305 Category : Nanotechnology Languages : en Pages : 139
Book Description
The biggest attraction of building nanometer structures is the emergence of novel properties and phenomena at these length scales. In the discipline of electronics particularly, nanoscale bridges the gap between the microscopic quantum world to the macroscopic classical world. The bridge can be tailored to effectively affect the material properties. One of the well-known phenomena that is altered at the nanoscale is the electron transport through a metal, i.e. the Ohm's law. As the size of the metal particle reduces to nanometer, Ohm's law breaks down due to trapping of a single electron charge, i.e. local charging, that prohibits the subsequent steam of electrons to pass through. This phenomenon is referred to as the Coulomb blockade, where the current is blocked below a threshold bias, VT. However, to observe a robust VT, the system has to be cooled to cryogenic temperatures. Here, fabrication and construction of a nano-system using directed self-assembled network of 1D necklace of 10 nm Au particles are described, which exhibits a robust single electron effect with a record high VT of 7.5 V at room temperature and a subsequent current, I rise as ( V/VT -- 1)&zgr;, where &zgr; is a critical constant, usually around 2. These physical parameters can be precisely tuned by tailoring the dimension and topology of the ensemble. The finding is important as nanoparticle based Single Electron Devices (SEDs) have become of great interest due to their orders of magnitude high sensitivity to gating. For over six decades of research on SEDs, it is clear that V T > 2 V at room temperature is required to make a robust device to eliminate the omnipresent "quantum noise" in these systems. Our system has not only shown a room temperature VT of well above 2 V but also its easy integrability with microelectronics circuits. Detailed scientific studies have been performed on the formation and structure of necklace array to understand the assembly process. Subsequent modification of the necklace array can be performed by nano-cementing to regulate its electrical and optoelectronic properties while maintaining the single electron effect. In the second aspect of the process, the device fabrication, a method implementing soft-lithography and electron beam has been developed to pattern the necklace monolayer with custom design at sub-micron levels. The technique confines the network of the necklaces to a width small enough that the current is limited to a single necklace array connecting two larger necklace network clusters. The approach allows fundamental and sophisticated measurements to be conducted to study mesoscale properties of disordered structures.
Author: Dietrich Alexander Dehlinger
Author: Manish Mittal
Author: Rongchao Jin
Author: Sivaraman Ramaswamy
Author: Shu Chien
Author: Shafigh Mehraeen
Author: Katsuhiko Ariga
Author: Ramanathan Nagarajan
Author: 
Author: Jason Kee Yang Ong