Soft Condensed Matter Daan Frenkel
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
2 a Primer on Polymer Colloids: Structure, Synthesis and Colloidal Stability
A. Al Shboul, F. Pierre, and J. P. Claverie 2 A primer on polymer colloids: structure, synthesis and colloidal stability 2.1 Introduction A colloid is a dispersion of very fine objects in a fluid [1]. These objects can be solids, liquids or gas, and the corresponding colloidal dispersion is then referred to as sus- pension, emulsion or foam. Colloids possess unique characteristics. For example, as their size is smaller than the wavelength of light, they scatter light. They also offer a large interfacial surface area, meaning that interfacial phenomena are of paramount importance in these dispersions. The weight of each dispersed particle being small, gravity and buoyancy forces are not sufficient to counteract the thermal random mo- tion of the particle, named Brownian motion (in tribute to the 19th century botanist Robert Brown who first characterized it). The particles do not remain in a dispersed state indefinitely: they will sooner or later aggregate (phase separation). Thus, thecol- loidal state is in general metastable and colloidal stability is one of the key features to take into account when working with colloids. Among all colloids, the polymer colloid family is one of the most widely inves- tigated [2]. Polymer colloids are used for a large number of applications, ranging from coatings, adhesives, inks, impact modifiers, drug-delivery vehicles, etc. The particles range in size from about 10 nm to 1 000 nm (1 μm) in diameter. They are usually spherical, but numerous other shapes have been observed. Polymer colloids are not uncommon in nature. For example, natural rubber latex, the secretion of the Hevea brasiliensis tree, is in fact a dispersion of polyisoprene nanoparticles in wa- ter. -
4. Fabrication of Polymer-Immobilized Colloidal Crystal Films (851Kb)
R&D Review of Toyota CRDL, Vol.45 No.1 (2014) 17- 22 17 Special Feature: Applied Nanoscale Morphology Research Report Fabrication of Polymer-immobilized Colloidal Crystal Films Masahiko Ishii Report received on Feb. 28, 2014 A fabrication method for polymer-immobilized colloidal crystal fi lms using conventional spray coating has been developed for application of the fi lms as practical colored materials. By controlling both the viscosity of the silica sphere-acrylic monomer dispersions and the wettability of the substrates, colloidal crystalline fi lms with brilliant iridescent colors were successfully obtained by spray coating and UV curing. The color could be controlled by adjusting both the sphere concentration and diameter. Scanning electron microscopy was applied to study the crystal structure of the coated fi lms, and revealed that the fi lms are composed of highly oriented face-centered-cubic grains with (111) planes parallel to the substrate surface. A method for utilizing the colloidal crystal fi lms as pigments was also proposed. Flakes obtained by crushing the colloidal crystal coated fi lms were added to a commercial clear paint and coated on a substrate. The coated fi lms exhibited iridescent colors that varies with viewing angle. Colloidal Crystal, Self-assembly, Silica, Polymeric Material, Spray Coating 1. Introduction arrays of monodispersed sub-micrometer sized spheres. They exhibit iridescent colors due to Bragg diffraction Jewels such as diamonds and rubies are beautiful, of visible light when they have a periodicity on the attracting the attention of people worldwide. Most of scale of the wavelength of the light. The most common these are natural minerals with crystalline structures. -
Plasmofluidic Single-Molecule Surface-Enhanced Raman
ARTICLE Received 24 Feb 2014 | Accepted 9 Jun 2014 | Published 7 Jul 2014 DOI: 10.1038/ncomms5357 Plasmofluidic single-molecule surface-enhanced Raman scattering from dynamic assembly of plasmonic nanoparticles Partha Pratim Patra1, Rohit Chikkaraddy1, Ravi P.N. Tripathi1, Arindam Dasgupta1 & G.V. Pavan Kumar1 Single-molecule surface-enhanced Raman scattering (SM-SERS) is one of the vital applications of plasmonic nanoparticles. The SM-SERS sensitivity critically depends on plasmonic hot-spots created at the vicinity of such nanoparticles. In conventional fluid-phase SM-SERS experiments, plasmonic hot-spots are facilitated by chemical aggregation of nanoparticles. Such aggregation is usually irreversible, and hence, nanoparticles cannot be re-dispersed in the fluid for further use. Here, we show how to combine SM-SERS with plasmon polariton-assisted, reversible assembly of plasmonic nanoparticles at an unstructured metal–fluid interface. One of the unique features of our method is that we use a single evanescent-wave optical excitation for nanoparticle assembly, manipulation and SM-SERS measurements. Furthermore, by utilizing dual excitation of plasmons at metal–fluid interface, we create interacting assemblies of metal nanoparticles, which may be further harnessed in dynamic lithography of dispersed nanostructures. Our work will have implications in realizing optically addressable, plasmofluidic, single-molecule detection platforms. 1 Photonics and Optical Nanoscopy Laboratory, h-cross, Indian Institute of Science Education and Research, Pune 411008, India. Correspondence and requests for materials should be addressed to G.V.P.K. (email: [email protected]). NATURE COMMUNICATIONS | 5:4357 | DOI: 10.1038/ncomms5357 | www.nature.com/naturecommunications 1 & 2014 Macmillan Publishers Limited. All rights reserved. -
Generation and Stability of Size-Adjustable Bulk Nanobubbles
www.nature.com/scientificreports OPEN Generation and Stability of Size-Adjustable Bulk Nanobubbles Based on Periodic Pressure Received: 10 September 2018 Accepted: 18 December 2018 Change Published: xx xx xxxx Qiaozhi Wang, Hui Zhao, Na Qi, Yan Qin, Xuejie Zhang & Ying Li Recently, bulk nanobubbles have attracted intensive attention due to the unique physicochemical properties and important potential applications in various felds. In this study, periodic pressure change was introduced to generate bulk nanobubbles. N2 nanobubbles with bimodal distribution and excellent stabilization were fabricated in nitrogen-saturated water solution. O2 and CO2 nanobubbles have also been created using this method and both have good stability. The infuence of the action time of periodic pressure change on the generated N2 nanobubbles size was studied. It was interestingly found that, the size of the formed nanobubbles decreases with the increase of action time under constant frequency, which could be explained by the diference in the shrinkage and growth rate under diferent pressure conditions, thereby size-adjustable nanobubbles can be formed by regulating operating time. This study might provide valuable methodology for further investigations about properties and performances of bulk nanobubbles. Nanobubbles are gaseous domains which could be found at the solid/liquid interface or in solution, known as surface nanobubbles (SNBs)1,2 and bulk nanobubbles (BNBs)3, respectively. For BNBs, generally recognized as spherical bubbles with the diameter of less than 1μm surrounded by liquid, though it has been observed frstly in 19814, the existence of long-lived BNBs is still a controversial subject as it is contrary to the classical theory5,6. -
Colloidal Crystals with a 3D Photonic Bandgap
Part I General Introduction I.1 Photonic Crystals A photonic crystal (PC) is a regularly structured material, with feature sizes on the order of a wavelength (or smaller), that exhibits strong interaction with light.1-3 The main concept behind photonic crystals is the formation of a 'photonic band gap'. For a certain range of frequencies, electromagnetic waves are diffracted by the periodic modulations in the dielectric constant of the PC forming (directional) stop bands. If the stop bands are wide enough to overlap for both polarization states along all crystal directions, the material is said to possess a complete photonic band gap (CPBG). In such a crystal, propagation of electromagnetic waves with frequencies lying within the gap is forbidden irrespective of their direction of propagation and polarization.1,2 This leads to the possibility to control the spontaneous emission of light. For example, an excited atom embedded in a PC will not be able to make a transition to a lower energy state as readily if the frequency of the emitted photon lies within the band gap, hence increasing the lifetime of the excited state.1,2 Photonic crystals with a (directional) stop gap can also have a significant effect on the spontaneous-emission rate.4 If a defect or mistake in the periodicity is introduced in the otherwise perfect crystal, localized photonic states in the gap will be created. A point defect could act like a microcavity, a line defect like a wave-guide, and a planar defect like a planar wave-guide. By introducing defects, light can be localized or guided along the defects modes.1,2 1 2 a b Figure I.1–1 Scanning electron micrograph (SEM) of a face-centered-cubic (fcc) colloidal crystal of closed-packed silica spheres (R = 110 nm). -
On Soft Matter
FASCINATING Research Soft MATTER Hard Work on Soft Matter What do silk blouses, diskettes, and the membranes of living cells have in common? All three are made barked on an unparalleled triumphal between the ordered structure of building blocks.“ And Prof. Helmuth march. Even information, which to- solids and the highly disordered gas. Möhwald, director of the “Interfaces” from soft matter: if individual molecules are observed, they appear disordered, however, on a larger, day frequently tends to be described These are typically supramolecular department at the MPIKG adds, “To as one of the most important raw structures and colloids in liquid me- supramolecular scale, they form ordered structures. Disorder and order interact, thereby affecting the put it in rather simplified terms, soft materials, can only be generated, dia. Particularly complex examples matter is unusual because its struc- properties of the soft material. At the MAX PLANCK INSTITUTES FOR POLYMER RESEARCH stored, and disseminated on a mas- occur in the area of biomaterials,” ture is determined by several weaker sive scale via artificial soft materials. says Prof. Reinhard Lipowsky, direc- forces. For this reason, its properties in Mainz and of COLLOIDS AND INTERFACES in Golm, scientists are focussing on this “soft matter”. Without light-sensitive coatings, tor of the “Theory” Division of the depend very much upon environ- there would be no microchip - and Max Plank Institute of Colloids and mental and production conditions.” nor would there be diskettes, CD- Interfaces in Golm near Potsdam The answers given by the three ROMs, and videotapes, which are all (MPIKG). Prof. Hans Wolfgang scientists are typical in that their made from coated plastics. -
Review Article Importance of Molecular Interactions in Colloidal Dispersions
Hindawi Publishing Corporation Advances in Condensed Matter Physics Volume 2015, Article ID 683716, 8 pages http://dx.doi.org/10.1155/2015/683716 Review Article Importance of Molecular Interactions in Colloidal Dispersions R. López-Esparza,1,2 M. A. Balderas Altamirano,1 E. Pérez,1 and A. Gama Goicochea1,3 1 Instituto de F´ısica, Universidad Autonoma´ de San Luis Potos´ı, 78290 San Luis Potos´ı, SLP, Mexico 2Departamento de F´ısica, Universidad de Sonora, 83000 Hermosillo, SON, Mexico 3Innovacion´ y Desarrollo en Materiales Avanzados A. C., Grupo Polynnova, 78211 San Luis Potos´ı, SLP, Mexico Correspondence should be addressed to A. Gama Goicochea; [email protected] Received 21 May 2015; Accepted 2 August 2015 Academic Editor: Jan A. Jung Copyright © 2015 R. Lopez-Esparza´ et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We review briefly the concept of colloidal dispersions, their general properties, and some of their most important applications, as well as the basic molecular interactions that give rise to their properties in equilibrium. Similarly, we revisit Brownian motion and hydrodynamic interactions associated with the concept of viscosity of colloidal dispersion. It is argued that the use of modern research tools, such as computer simulations, allows one to predict accurately some macroscopically measurable properties by solving relatively simple models of molecular interactions for a large number of particles. Lastly, as a case study, we report the prediction of rheological properties of polymer brushes using state-of-the-art, coarse-grained computer simulations, which are in excellent agreement with experiments. -
Soft Matter Theory
Soft Matter Theory K. Kroy Leipzig, 2016∗ Contents I Interacting Many-Body Systems 3 1 Pair interactions and pair correlations 4 2 Packing structure and material behavior 9 3 Ornstein{Zernike integral equation 14 4 Density functional theory 17 5 Applications: mesophase transitions, freezing, screening 23 II Soft-Matter Paradigms 31 6 Principles of hydrodynamics 32 7 Rheology of simple and complex fluids 41 8 Flexible polymers and renormalization 51 9 Semiflexible polymers and elastic singularities 63 ∗The script is not meant to be a substitute for reading proper textbooks nor for dissemina- tion. (See the notes for the introductory course for background information.) Comments and suggestions are highly welcome. 1 \Soft Matter" is one of the fastest growing fields in physics, as illustrated by the APS Council's official endorsement of the new Soft Matter Topical Group (GSOFT) in 2014 with more than four times the quorum, and by the fact that Isaac Newton's chair is now held by a soft matter theorist. It crosses traditional departmental walls and now provides a common focus and unifying perspective for many activities that formerly would have been separated into a variety of disciplines, such as mathematics, physics, biophysics, chemistry, chemical en- gineering, materials science. It brings together scientists, mathematicians and engineers to study materials such as colloids, micelles, biological, and granular matter, but is much less tied to certain materials, technologies, or applications than to the generic and unifying organizing principles governing them. In the widest sense, the field of soft matter comprises all applications of the principles of statistical mechanics to condensed matter that is not dominated by quantum effects. -
Colloidal Crystal: Emergence of Long Range Order from Colloidal Fluid
Colloidal Crystal: emergence of long range order from colloidal fluid Lanfang Li December 19, 2008 Abstract Although emergence, or spontaneous symmetry breaking, has been a topic of discussion in physics for decades, they have not entered the set of terminologies for materials scientists, although many phenomena in materials science are of the nature of emergence, especially soft materials. In a typical soft material, colloidal suspension system, a long range order can emerge due to the interaction of a large number of particles. This essay will first introduce interparticle interactions in colloidal systems, and then proceed to discuss the emergence of order, colloidal crystals, and finally provide an example of applications of colloidal crystals in light of conventional molecular crystals. 1 1 Background and Introduction Although emergence, or spontaneous symmetry breaking, and the resultant collective behav- ior of the systems constituents, have manifested in many systems, such as superconductivity, superfluidity, ferromagnetism, etc, and are well accepted, maybe even trivial crystallinity. All of these phenonema, though they may look very different, share the same fundamental signature: that the property of the system can not be predicted from the microscopic rules but are, \in a real sense, independent of them. [1] Besides these emergent phenonema in hard condensed matter physics, in which the interaction is at atomic level, interactions at mesoscale, soft will also lead to emergent phenemena. Colloidal systems is such a mesoscale and soft system. This size scale is especially interesting: it is close to biogical system so it is extremely informative for understanding life related phenomena, where emergence is origin of life itself; it is within visible light wavelength, so that it provides a model system for atomic system with similar physics but probable by optical microscope. -
Universality in Spectral Condensation Induja Pavithran1, Vishnu R
www.nature.com/scientificreports OPEN Universality in spectral condensation Induja Pavithran1, Vishnu R. Unni2*, Alan J. Varghese3, D. Premraj3, R. I. Sujith3,4*, C. Vijayan1, Abhishek Saha2, Norbert Marwan4 & Jürgen Kurths4,5,6 Self-organization is the spontaneous formation of spatial, temporal, or spatiotemporal patterns in complex systems far from equilibrium. During such self-organization, energy distributed in a broadband of frequencies gets condensed into a dominant mode, analogous to a condensation phenomenon. We call this phenomenon spectral condensation and study its occurrence in fuid mechanical, optical and electronic systems. We defne a set of spectral measures to quantify this condensation spanning several dynamical systems. Further, we uncover an inverse power law behaviour of spectral measures with the power corresponding to the dominant peak in the power spectrum in all the aforementioned systems. During self-organization, an ordered pattern emerges from an initially disordered state. In dynamical systems, a pattern can be any regularly repeating arrangements in space, time or both1. For example, a laser emits random wave tracks like a lamp until the critical pump power, above which the laser emits light as a single coherent wave track with high-intensity2. A macroscopic change is observed in the laser system as a long-range pattern emerges in time. Another example is the Rayleigh–Bénard system. For lower temperature gradients, the fuid parcels move randomly. As the temperature gradient is increased, a rolling motion sets in and the fuid parcels behave coherently to form spatially extended patterns. Te initial random pattern can be regarded as a superposition of a variety of oscillatory modes and eventually some oscillatory modes dominate, resulting in the emergence of a spatio-temporal pattern3,4. -
Surface Plasmon Resonance Study of the Purple Gold
SURFACE PLASMON RESONANCE STUDY OF THE PURPLE GOLD (AuAl2) INTERMETALLIC, pH-RESPONSIVE FLUORESCENCE GOLD NANOPARTICLES, AND GOLD NANOSPHERE ASSEMBLY Panupon Samaimongkol Dissertation submitted to the faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy In Physics Hans D. Robinson, Chair Giti Khodaparast Chenggang Tao Webster Santos June 22, 2018 Blacksburg, Virginia Keywords: Surface plasmons (SPs), Localized surface plasmon resonances (LSPRs), Kretschmann configuration, Surface plasmon-enhanced fluorescence (PEF) spectroscopy, Self-Assembly, Nanoparticles Copyright 2018, Panupon Samaimongkol i SURFACE PLASMON RESONANCE STUDY OF THE PURPLE GOLD (AuAl2) INTERMETALLIC, pH-RESPONSIVE FLUORESCENCE GOLD NANOPARTICLES, AND GOLD NANOSPHERE ASSEMBLY Panupon Samaimongkol ABSTRACT (academic) In this dissertation, I have verified that the striking purple color of the intermetallic compound AuAl2, also known as purple gold, originates from surface plasmons (SPs). This contrasts to a previous assumption that this color is due to an interband absorption transition. The existence of SPs was demonstrated by launching them in thin AuAl2 films in the Kretschmann configuration, which enables us to measure the SP dispersion relation. I observed that the SP energy in thin films of purple gold is around 2.1 eV, comparable to previous work on the dielectric function of this material. Furthermore, SP sensing using AuAl2 also shows the ability to measure the change in the refractive index of standard sucrose solution. AuAl2 in nanoparticle form is also discussed in terms of plasmonic applications, where Mie scattering theory predicts that the particle bears nearly uniform absorption over the entire visible spectrum with an order magnitude higher absorption than efficient light-absorbing carbonaceous particle also known a carbon black. -
D0tc00217h4.Pdf
Electronic Supplementary Material (ESI) for Journal of Materials Chemistry C. This journal is © The Royal Society of Chemistry 2020 Electronic Supporting Information What is the role of planarity and torsional freedom for aggregation in a -conjugated donor-acceptor model oligomer? Stefan Wedler1, Axel Bourdick2, Stavros Athanasopoulos3, Stephan Gekle2, Fabian Panzer1, Caitlin McDowell4, Thuc-Quyen Nguyen4, Guillermo C. Bazan5, Anna Köhler1,6* 1 Soft Matter Optoelectronics, Experimentalphysik II, University of Bayreuth, Bayreuth 95440, Germany. 2Biofluid Simulation and Modeling, Theoretische Physik VI, Universität Bayreuth, Bayreuth 95440, Germany 3Departamento de Física, Universidad Carlos III de Madrid, Avenida Universidad 30, 28911 Leganés, Madrid, Spain. 4Center for Polymers and Organic Solids, Departments of Chemistry & Biochemistry and Materials, University of California, Santa Barbara 5Departments of Chemistry and Chemical Engineering, National University of Singapore, Singapore, 119077 6Bayreuth Institute of Macromolecular Research (BIMF) and Bavarian Polymer Institute (BPI), University of Bayreuth, 95440 Bayreuth, Germany. *e-mail: [email protected] 1 1 Simulated spectra Figure S1.1: Single molecule TD-DFT simulated absorption spectra at the wB97XD/6-31G** level for the TT and CT molecules. TT absorption at the ground state twisted cis and trans configurations is depicted. Vertical transition energies have been broadened by a Gaussian function with a half-width at half-height of 1500cm-1. Figure S1.2: Simulated average CT aggregate absorption spectrum. The six lowest vertical transition transition energies for CT dimer configurations taken from the MD simulations have been computed with TD-DFT at the wB97XD/6-31G** level. Vertical transition energies have been broadened by a Gaussian function with a half-width at half-height of 1500cm-1.