Lyotropic Liquid Crystals as Templates for the Synthesis of Silver Nanoparticles
Lyotropic Liquid Crystals as Templates for the Synthesis of Silver Nanoparticles

Author: Dmitry Kushnikovskiy

Publisher:

Published: 2017

Total Pages: 0

ISBN-13:

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This thesis is focused on the synthesis of silver nanoparticles in various lyotropic liquid crystalline phases formed by biologically friendly surfactants with or without dodecyltrimethylammonium-DNA complex in aqueous solution with different additives. In all cases, silver ions were reduced by components contained in the system, no additional reductants were employed. In total, four different systems have been investigated as potential templates for the nanoparticle preparation. Two different synthetic strategies have been used. Firstly, nanoparticles were synthesized by the chemical reduction of silver ions by the nonionic or zwitterionic surfactant molecules which were used to form the liquid crystalline phase. Secondly, nanoparticles have been synthesized by UV irradiation of DNA-containing liquid crystals where DNA acts as templating and photosensitizing agent. At the first stage, an Ag-DNA complex is formed by embedding silver ions into the double helix. Illumination of this complex with UV light that is absorbed by the nucleobases induced the formation of nanoparticles within the DNA double helix.The effect of the formation of silver nanoparticles on the lyotropic liquid crystalline phase was investigated by 2H and 31P NMR spectroscopy, small angle X-ray scattering, and polarizing optical microscopy. The influence of the template mesophase on the formation rate and nanoparticle size and morphology was studied using UV-spectroscopy, transmission electron and atomic force microscopy techniques. ; eng

Lyotropic Liquid Crystals
Lyotropic Liquid Crystals

Author: Ingo Dierking

Publisher: Oxford University Press

Published: 2024-07-16

Total Pages: 225

ISBN-13: 0192653822

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This book aims to review the field of lyotropic liquid crystals from amphiphilic to colloidal systems, bridging the gap between the two worlds of lyotropics and thermotropics by showing that many of the features observed in standard thermotropic liquid crystals may also be observed in lyotropic systems and vice versa. Indeed, for a long time, lyotropic liquid crystals have been overshadowed by their thermotropic counterparts, mainly due to the potential for application of the latter in the display industry. This picture has somewhat shifted over the last decade, with numerous novel lyotropic systems having been discovered and formulated, bringing to light their importance in wider scientific research. For example, the understanding of viruses forming self-assembled ordered phases has largely increased as mineral liquid crystals and clays have experienced a renaissance leading to fundamental research and work on structure formation in nanotechnology. Similarly, nano-rods, nano-wires, nanotubes and 2D materials like graphene oxide and others have been shown to exhibit liquid crystalline behaviour, which may be exploited in self-assembly, drug delivery or biosensors. Cellulose nanocrystals have become an important and popular field of research. The self-assembly of short chain DNA fragments has led to liquid crystal behaviour previously thought to be impossible. Chromonics were shown to exhibit fascinating physical properties, and the combination of active fluids with liquid crystals has opened a whole new field of research to be explored - 'living liquid crystals'.

New Trends in Lyotropic Liquid Crystals
New Trends in Lyotropic Liquid Crystals

Author: Ingo Dierking

Publisher: MDPI

Published: 2020-11-02

Total Pages: 252

ISBN-13: 3039433423

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Liquid crystals (LCs) were discovered more than a century ago, and were, for a long time, treated as a physical curiosity, until the development of flat panel screens and display devices caused a revolution in the information display industry, and in fact in society. There would be no mobile phones without liquid crystals, no flat screen TVs or computer monitors, no virtual reality, just to name a few of the applications that have changed our whole world of vision and perception. All of these inventions are based on liquid crystals that are formed through a change in temperature, thermotropic LCs. However, there is another form of liquid crystals, described even earlier, yet much less talked about; the lyotropic liquid crystals that occur through the change of concentration of some molecules in a solvent. These are found in abundance in nature, making up the cell membranes, and are used extensively in the food, detergents and cosmetics industries. In this collection of articles by experts in their respective research areas, we bring together some of the most recent and innovative aspects of lyotropic liquid crystals, which we believe will drive future research and set novel trends in this field.

Liquid Crystals With Nano And Microparticles (In 2 Volumes)
Liquid Crystals With Nano And Microparticles (In 2 Volumes)

Author: Jan P F Lagerwall

Publisher: World Scientific

Published: 2016-10-10

Total Pages: 944

ISBN-13: 9814619272

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'The overall book content is excellently coordinated to form a synchronised story, interesting to a broad scientific audience … The book summarises the present knowledge in the field, introduces fundamental concepts to the beginners, describes key measuring methods and presents several different typical demonstrative systems, some of them exhibiting an extraordinary rich spectrum of structures and superstructures. I am sure that with time the book will become an attractor to a broad audience (physicists, chemists, material scientists, engineers, etc.), ranging from students, beginners in the field to experienced researchers. To summarise, this is the book that I have been missing on my bookshelf.'Liquid Crystals TodayWhile liquid crystals are today widely known for their successful application in flat panel displays (LCDs), academic liquid crystal research is more and more targeting situations where these anisotropic fluids are put to completely different use, in varying contexts. A particularly strong focus is on colloidal liquid crystals, where particles, bubbles or drops are dispersed in a liquid crystal phase. The liquid crystal can act as a host phase, with the inclusions constituting foreign guests that disturb the local order in interesting ways, often resulting in large-scale positional arrangement and/or uniform alignment of the guests. But it may also be formed by solid particles themselves, if these are of nanoscale dimensions and of disc- or rod-shape, and if they are suspended in an isotropic liquid host at sufficient concentration.This book aims to cover both the modern research tracks, gathering pioneering researchers of the different subfields to give a concise overview of the basis as well as the prospects of their respective specialties. The scope spans from curiosity-driven fundamental scientific research to applied sciences. Over the course of the next decade, the former is likely to generate new tracks of the latter type, considering the exploratory and productive phase of this young research field.

Complex-shaped Metal Nanoparticles
Complex-shaped Metal Nanoparticles

Author: Tapan K. Sau

Publisher: John Wiley & Sons

Published: 2012-05-07

Total Pages: 583

ISBN-13: 3527652590

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The past few years have witnessed the development of non-spherical metal nanoparticles with complex morphologies, which offer tremendous potential in materials science, chemistry, physics and medicine. Covering all important aspects and techniques of preparation and characterization of metal nanoparticles with controlled morphology and architecture, this book provides a sound overview - from the basics right up to recent developments. Renowned research scientists from all over the world present the existing knowledge in the field, covering theory and modeling, synthesis and properties of these nanomaterials. By emphasizing the underlying concepts and principles in detail, this book enables researchers to fully recognize the future research scope and the application potential of the complex-shaped metal nanoparticles, inspiring further research in this field.

Noble Metal Nanoparticles
Noble Metal Nanoparticles

Author: Ignác Capek

Publisher: Springer

Published: 2017-07-20

Total Pages: 568

ISBN-13: 4431565566

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This book introduces the reader the chemistry of reaction approaches by which noble metal nanoparticles are synthesized, including synthetic approaches using the Brust–Schiffrin method , a high-temperature solution-phase synthesis, polymer and biological entities, weak and strong reducing and capping agents, the low and high temperatures, various additives and various novel approaches such as plasma, ionic liquids, UV light and gamma rays and others. This book starts with a brief overview of foundation work concerned with the chapter topics such as nanomaterials, nanoscience, surface-capping molecules, traditional and nontraditional reduction agents, In addition, chemical and physical properties of noble metal nanoparticles with different structures and elements such as monolayered clusters, nanorods, and bimetallic nanoparticles are described comprehensively. The aim is to summarize the fundamentals and mechanistic approaches in the preparation and characterization of metal colloidal nanoparticles and dispersions. In this way the reader is provided with a systematic and coherent picture of the interesting field of nanoscience based on noble metal colloidal nanoparticles. Intended as a wide-ranging overview, the book is a resource for novices in the field as well as for specialists, particularly those scientists working in the area of nanoparticle synthesis. Nanoscience and nanotechnology are discussed from the chemist’s point of view. Therefore, this volume describes in detail the terms, definitions, theories, experiments, and techniques dealing with the synthesis of noble metal nanoparticles. The material presented here is essential reading for research chemists, technologists, and engineers in the fields of specialty nanomaterials and metal industries, and also is highly valuable for researchers in university, institutional, and governmental laboratories, especially for those at advanced stages of their careers.

Liquid Crystals
Liquid Crystals

Author: Carsten Tschierske

Publisher: Springer Science & Business Media

Published: 2012-01-24

Total Pages: 419

ISBN-13: 3642275915

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Fluorinated Liquid Crystals: Design of Soft Nanostructures and Increased Complexity of Self-Assembly by Perfluorinated Segments, by Carsten Tschierske Liquid Crystalline Crown Ethers, by Martin Kaller and Sabine Laschat Star-Shaped Mesogens – Hekates: The Most Basic Star Structure with Three Branches, by Matthias Lehmann DNA-Based Soft Phases, by Tommaso Bellini, Roberto Cerbino and Giuliano Zanchetta Polar and Apolar Columnar Phases Made of Bent-Core Mesogens, by N. Vaupotič, D. Pociecha and E. Gorecka Spontaneous Achiral Symmetry Breaking in Liquid Crystalline Phases, by H. Takezoe Nanoparticles in Liquid Crystals and Liquid Crystalline Nanoparticles, by Oana Stamatoiu, Javad Mirzaei, Xiang Feng and Torsten Hegmann Stimuli-Responsive Photoluminescent Liquid Crystals, by Shogo Yamane, Kana Tanabe, Yoshimitsu Sagara and Takashi Kato

Templating the Synthesis of Compound Semiconductor Nanostructures Using Microemulsions and Lyotropic Liquid Crystals
Templating the Synthesis of Compound Semiconductor Nanostructures Using Microemulsions and Lyotropic Liquid Crystals

Author:

Publisher:

Published: 2005

Total Pages: 171

ISBN-13:

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In this work, novel synthetic strategies have been developed that employ templates to control the size, shape, and composition of compound semiconductor nanostructures at room temperature. The templates were formed by self-assembly of a poly (ethylene oxide)-poly (propylene oxide)-poly (ethylene oxide) (PEO-PPO-PEO) amphiphilic block copolymer in the presence of a polar solvent and a less polar one. PEO-PPO-PEO block copolymers, due to their amphiphilic character, exhibit very rich structural polymorphism when dissolved in selective solvents of different polarity, and can attain a number of microstructures such as spheres, cylinders, and lamellae. Using these self-assembled structures as nanoreactors, a variety of semiconductor nanocrystals were obtained that acquired the geometry of the template. Luminescent quantum dots were synthesized by a microemulsion-gas contacting technique that exploited the spherical nanodroplets of a microemulsion to form numerous identical nanoreactors. ZnSe quantum dots were grown by reacting hydrogen selenide gas with diethylzinc dissolved in the heptane nanodroplets of a microemulsion formed by self-assembly of a PEO-PPO-PEO amphiphilic block copolymer in formamide. A single nanocrystal is grown in each nanodroplet, thus allowing good control of particle size by manipulation of the initial diethylzinc concentration in the heptane. The microemulsion-encapsulated nanocrystals exhibit size-dependent luminescence and their photoluminescence spectra remain unchanged over a period of several months. The ability of the technique to tune the chemical composition of the nanocrystals was demonstrated with the growth of CdSe quantum dots, which was realized after substituting diethylzinc with dimethylcadmium. Lyotropic liquid crystals of the PEO-PPO-PEO/heptane/formamide self-assembled system were employed to control the shape and morphology of semiconductor nanostructures. ZnSe quantum dots, nanowires and nanodisks were grown inside the spherical, cylindrical, and planar nanodomains of the cubic, hexagonal, and lamellar liquid crystalline phases of the above ternary system, respectively. The phase behavior of the ternary system at room temperature was investigated in detail to identify the compositions corresponding to the phase regions of interest. (Abstract shortened by UMI.).