			Home About us Contact

Soft Materials (soft + material)

Distribution by Scientific Domains

Polymers and Materials Science	44%
Chemistry	44%

Selected Abstracts

Luminescent Soft Material: Two New Europium-Based Ionic Liquids

HELVETICA CHIMICA ACTA, Issue 11 2009
Sifu Tang
Abstract Two new Eu-based ionic liquid systems, [C4mim][DTSA],:,[Eu(DTSA)3] and 2[C4mim] [DTSA],:,[Eu(DTSA)3] were synthesized at 120° under inert conditions from 1-butyl-1-methylimidazolium ditoluenesulfonylamide ([C4mim][DTSA]). The identity and purity of the synthesized compounds were confirmed by elemental analysis, IR, Raman, and 1H-NMR spectroscopy. As they solidify below 100° as glasses they qualify as ionic liquids. Fluorescence measurements show that the materials exhibit a strong red luminescence of high color purity. Therefore, they have the potential to be used for optical applications such as in emission displays. [source]

Oxygen-Generating Gel Systems Induced by Visible Light

ADVANCED FUNCTIONAL MATERIALS, Issue 5 2010
Kosuke Okeyoshi
Abstract Toward complete artificial photosynthesis systems to generate hydrogen and oxygen using visible light and water, oxygen-generating gel systems are designed and fabricated using the electrostatic interactions of ionic functional groups and steric effects of a polymer network. By using a graft polymer chain with Ru(bpy)32+ units as sensitizers to closely arrange RuO2 nanoparticles as catalyst, the functional groups transmit multiple electrons cooperatively to generate oxygen. In this paper, a novel strategy is shown to design a hierarchical network structure using colloidal nanoparticles and macromonomers. Such a soft material to oxidize water inside a hydrogel is useful as a solar-energy converting system. [source]

Numerical simulation of the fracture process in cutting heterogeneous brittle material

INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 13 2002
H. Y. Liu
Abstract The process of cutting homogeneous soft material has been investigated extensively. However, there are not so many studies on cutting heterogeneous brittle material. In this paper, R-T2D (Rock and Tool interaction), based on the rock failure process analysis model, is developed to simulate the fracture process in cutting heterogeneous brittle material. The simulated results reproduce the process involved in the fragmentation of rock or rock-like material under mechanical tools: the build-up of the stress field, the formation of the crushed zone, surface chipping, and the formation of the crater and subsurface cracks. Due to the inclusion of heterogeneity in the model, some new features in cutting brittle material are revealed. Firstly, macroscopic cracks sprout at the two edges of the cutter in a tensile mode. Then with the tensile cracks releasing the confining pressure, the rock in the initially high confining pressure zone is compressed into failure and the crushed zone gradually comes into being. The cracked zone near the crushed zone is always available, which makes the boundary of the crushed zone vague. Some cracks propagate to form chipping cracks and some dip into the rock to form subsurface cracks. The chipping cracks are mainly driven to propagate in a tensile mode or a mixed tensile and shear mode, following curvilinear paths, and finally intersect with the free surface to form chips. According to the simulated results, some qualitative and quantitative analyses are performed. It is found that the back rake angle of the cutter has an important effect on the cutting efficiency. Although the quantitative analysis needs more research work, it is not difficult to see the promise that the numerical method holds. It can be utilized to improve our understanding of tool,rock interaction and rock failure mechanisms under the action of mechanical tools, which, in turn, will be useful in assisting the design of fragmentation equipment and fragmentation operations. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Comparison of the Temperature-Dependent Ferroelastic Behavior of Hard and Soft Lead Zirconate Titanate Ceramics

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2010
Mie Marsilius
The ferroelastic properties of a hard acceptor-doped lead zirconate titanate (PZT) ceramic are investigated between room temperature and 300°C. Comparison with a soft PZT shows that acceptor doping has a stronger influence on mechanically induced domain switching than on switching caused by electric fields. A quantitative analysis of spontaneous and remanent strain and polarization indicates that poling in the soft material is dominated by 180° domain processes, while non-180° processes dominate the strain behavior. If the mechanical load exceeds a threshold level, the "hardening" effect of the acceptor doping vanishes, and hard and soft materials behave identically. The results are discussed based on the defect dipole model and the charge drift model for hardening and aging in acceptor-doped ferroelectric ceramics. [source]

Architecture of Supramolecular Soft Functional Materials: From Understanding to Micro-/Nanoscale Engineering

ADVANCED FUNCTIONAL MATERIALS, Issue 19 2010
Jing-Liang Li
Abstract This article gives an overview of the current progress of a class of supramolecular soft materials consisting of fiber networks and the trapped liquid. After discussing the up-to-date knowledge on the types of fiber networks and the correlation to the rheological properties, the gelation mechanism turns out to be one of the key subjects for this review. In this concern, the following two aspects will be focused upon: the single fiber network formation and the multi-domain fiber network formation of this type of material. Concerning the fiber network formation, taking place via nucleation, and the nucleation-mediated growth and branching mechanism, the theoretical basis of crystallographic mismatch nucleation that governs fiber branching and formation of three-dimensional fiber networks is presented. In connection to the multi-domain fiber network formation, which is governed by the primary nucleation and the subsequent formation of single fiber networks from nucleation centers, the control of the primary nucleation rate will be considered. Based on the understanding on the the gelation mechanism, the engineering strategies of soft functional materials of this type will be systematically discussed. These include the control of the nucleation and branching-controlled fiber network formation in terms of tuning the thermodynamic driving force of the gelling system and introducing suitable additives, as well as introducing ultrasound. Finally, a summary and the outlook of future research on the basis of the nucleation-growth-controlled fiber network formation are given. [source]

Architecture of Supramolecular Soft Functional Materials: From Understanding to Micro-/Nanoscale Engineering

Harnessing Surface Wrinkle Patterns in Soft Matter

ADVANCED FUNCTIONAL MATERIALS, Issue 16 2010
Shu Yang
Abstract Mechanical instabilities in soft materials, specifically wrinkling, have led to the formation of unique surface patterns for a wide range of applications that are related to surface topography and its dynamic tuning. In this progress report, two distinct approaches for wrinkle formation, including mechanical stretching/releasing of oxide/PDMS bilayers and swelling of hydrogel films confined on a rigid substrate with a depth-wise modulus gradient, are discussed. The wrinkling mechanisms and transitions between different wrinkle patterns are studied. Strategies to control the wrinkle pattern order and characteristic wavelength are suggested, and some efforts in harnessing topographic tunability in elastomeric PDMS bilayer wrinkled films for various applications, including tunable adhesion, wetting, microfluidics, and microlens arrays, are highlighted. The report concludes with perspectives on the future directions in manipulation of pattern formation for complex structures, and potential new technological applications. [source]

Soft Langmuir,Blodgett Technique for Hard Nanomaterials

ADVANCED MATERIALS, Issue 29 2009
Somobrata Acharya
Abstract Materials and their assemblies of dimensions down to a few nanometers have attracted considerable scientific interest in physical, chemical, and biological sciences because of unique properties not available in their bulk counterparts. The Langmuir,Blodgett (LB) technique allows rigid nanomaterials to be aligned in particular structures through a flexible assembly process at liquid interfaces. In this review, we summarize the development of assembly of hard nanomaterials using soft LB techniques. An initial summary of the basic features of nanomaterials will include dimension-related effects, synthesis, characterization, and analysis, and will be followed by examples of LB assemblies of nanomaterials described according to their morphology: nanoparticles, nanorods, nanowires, nanotubes, and nanosheets. Some of the nanomaterials have been fabricated in orientation-controlled morphologies, and have been incorporated into prototype devices for gas sensing and photocurrent transport. In the final part of this review, the challenges remaining for LB techniques of hard nanomaterials will be overviewed, and will include a comparison with the widely-used LB technique involving soft materials. [source]

Density functional theory for chemical engineering: From capillarity to soft materials

AICHE JOURNAL, Issue 3 2006
Jianzhong Wu
Abstract Understanding the microscopic structure and macroscopic properties of condensed matter from a molecular perspective is important for both traditional and modern chemical engineering. A cornerstone of such understanding is provided by statistical mechanics, which bridges the gap between molecular events and the structural and physiochemical properties of macro- and mesoscopic systems. With ever-increasing computer power, molecular simulations and ab initio quantum mechanics are promising to provide a nearly exact route to accomplishing the full potential of statistical mechanics. However, in light of their versatility for solving problems involving multiple length and timescales that are yet unreachable by direct simulations, phenomenological and semiempirical methods remain relevant for chemical engineering applications in the foreseeable future. Classical density functional theory offers a compromise: on the one hand, it is able to retain the theoretical rigor of statistical mechanics and, on the other hand, similar to a phenomenological method, it demands only modest computational cost for modeling the properties of uniform and inhomogeneous systems. Recent advances are summarized of classical density functional theory with emphasis on applications to quantitative modeling of the phase and interfacial behavior of condensed fluids and soft materials, including colloids, polymer solutions, nanocomposites, liquid crystals, and biological systems. Attention is also given to some potential applications of density functional theory to material fabrications and biomolecular engineering. © 2005 American Institute of Chemical Engineers AIChE J, 2006 [source]

Comparison of the Temperature-Dependent Ferroelastic Behavior of Hard and Soft Lead Zirconate Titanate Ceramics

Filler networks in elastomers

MACROMOLECULAR SYMPOSIA, Issue 1 2003
Françoise Ehrburger-Dolle
Abstract Elastomers are soft materials that can be reinforced by dispersing into them nanosized solid particles. Common examples of the latter are silica or carbon black aggregates. However, the mechanism of reinforcement is still not yet fully understood. Our work consists in investigating by small-angle X-ray scattering (SAXS) the structure of the aggregate network spreading throughout the matrix in the initial sample and its modification during and after straining (elongation). The goal is to relate the macroscopic mechanical behaviour with the structure of the aggregate network. The present paper is a qualitative overview of recent results obtained on well defined composites. [source]

Structural colored gels for tunable soft photonic crystals

THE CHEMICAL RECORD, Issue 2 2009
Mohammad Harun-ur-Rashid
Abstract A periodically ordered interconnecting porous structure can be embodied in chemical gels by using closest-packed colloidal crystals as templates. The interconnecting porosity not only provides a quick response but also endows the porous gels with structural color arising from coherent Bragg optical diffraction. The structural colors revealed by porous gels can be regulated by several techniques, and thus, it is feasible to obtain desirable, smart, soft materials. A well-known thermosensitive monomer, N -isopropylacrylamide (NIPA), and other minor monomers were used to fabricate various structural colored gels. The selection of minor monomers depended on the targeted properties. This review focuses on the synthesis of templates, structural colored porous gels, and the applications of structural colored gel as smart soft materials for tunable photonic crystals. © 2009 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 9: 87,105; 2009: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20169 [source]

Temporal-Spatial Structure of Intraplate Uplift in the Qinghai-Tibet Plateau

ACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 1 2010
Dewei LI
Abstract: The intraplate uplift of the Qinghai-Tibet Plateau took place on the basis of breakup and assembly of the Precambrian supercontinent, and southward ocean-continent transition of the Proto-, Paleo-, Meso- and Neo-Tethys during the Caledonian, Indosinian, Yanshanian and Early Himalayan movements. The intraplate tectonic evolution of the Qinghai-Tibet Plateau underwent the early stage of intraplate orogeny characterized by migrational tectonic uplift, horizontal movement and geological processes during 180,7 Ma, and the late stage of isostatic mountain building characterized by pulsative rapid uplift, vertical movement and geographical processes since 3.6 Ma. The spatial-temporal evolution of the intraplate orogeny within the Qinghai-Tibet Plateau shows a regular transition from the northern part through the central part to the southern part during 180,120 Ma, 65,35 Ma, and 25,7 Ma respectively, with extensive intraplate faulting, folding, block movement, magmatism and metallogenesis. Simultaneous intraplate orogeny and basin formation resulted from crustal rheological stratification and basin-orogen coupling that was induced by lateral viscous flow in the lower crust. This continental dynamic process was controlled by lateral flow of hot and soft materials within the lower crust because of slab dehydration and melted mantle upwelling above the subducted plates during the southward Tethyan ocean-continent transition processes or asthenosphere diapirism. Intraplate orogeny and basin formation were irrelevant to plate collision. The Qinghai-Tibet Plateau as a whole was actually formed by the isostatic mountain building processes since 3.6 Ma that were characterized by crust-scale vertical movement, and integral rapid uplift of the plateau, accompanied by isostatic subsidence of peripheral basins and depressions, and great changes in topography and environment. A series of pulsative mountain building events, associated with gravity equilibrium and isostatic adjustment of crustal materials, at 3.6 Ma, 2.5 Ma, 1.8,1.2 Ma, 0.9,0.8 Ma and 0.15,0.12 Ma led to the formation of a composite orogenic belt by unifying the originally relatively independent Himalayas, Gangdisê, Tanghla, Longmenshan, Kunlun, Altyn Tagh, and Qilian mountains, and the formation of the complete Qinghai-Tibet Plateau with a unified mountain root after Miocene uplift of the plateau as a whole. [source]

Structural Diversity in the Self-Assembly of Pseudopeptidic Macrocycles

CHEMISTRY - A EUROPEAN JOURNAL, Issue 4 2010
Ignacio Alfonso Dr.
Abstract The self-assembling abilities of several pseudopeptidic macrocycles have been thoroughly studied both in the solid (SEM, TEM, FTIR) and in solution (NMR, UV, CD, FTIR) states. Detailed microscopy revealed large differences in the morphology of the self-assembling micro/nanostructures depending on the macrocyclic chemical structures. Self-assembly was triggered by the presence of additional methylene groups or by changing from para to meta geometry of the aromatic phenylene backbone moiety. More interestingly, the nature of the side chain also plays a fundamental role in some of the obtained nanostructures, thus producing structures from long fibers to hollow spheres. These nanostructures were obtained in different solvents and on different surfaces, thus implying that the chemical information for the self-assembly is contained in the molecular structure. Dilution NMR studies (chemical shift and self-diffusion rates) suggest the formation of incipient aggregates in solution by a combination of hydrogen-bonding and ,,, interactions, thus implicating amide and aryl groups, respectively. Electronic spectroscopy further supports the ,,, interactions because the compounds that lead to fibers show large hypochromic shifts in the UV spectra. Moreover, the fiber-forming macrocycles also showed a more intense CD signature. The hydrogen-bonding interactions within the nanostructures were also characterized by attenuated total-reflectance FTIR spectroscopy, which allowed us to monitor the complete transition from the solution to the dried nanostructure. Overall, we concluded that the self-assembly of this family of pseudopeptidic macrocycles is dictated by a synergic action of hydrogen-bonding and ,,, interactions. The feasibility and geometrical disposition of these interactions finally render a hierarchical organization, which has been rationalized with a proposal of a model. The understanding of the process at the molecular level has allowed us to prepare hybrid soft materials. [source]

Star Mesogens (Hekates),Tailor-Made Molecules for Programming Supramolecular Functionality

CHEMISTRY - A EUROPEAN JOURNAL, Issue 15 2009
Matthias Lehmann
Abstract Hekates: Modular synthesis of star-shaped molecules affords mesogens with various functional units and incompatible peripheral chains (see figure). The supramolecular order in the complex, soft, liquid-crystalline, functional materials can be programmed by variation of the elements of diversity at a meso- and nanoscale. This concept article focuses on the simplest branched liquid crystalline (LC) molecules,the three-armed mesogens with arms symmetrically linked to the core. They are basic but fascinating mesogens for the exploration of self-assembling processes into complex, functional, soft materials. Quite a large number of elements of diversity provide the possibility to synthetically program such star-shaped molecules and to control phase formation, if aggregation processes are fully understood. Recently, ABC-cores opened the way to non-symmetric mesogens and, therefore, to the concept of multifunctional materials with defined nanostructures. In the article this outstanding family of mesogens is classified, their peculiar molecular structure and self-assembly are discussed and potential applications are presented, in which this type of mesogen may be beneficial. Dieser Konzeptbeitrag stellt die einfachsten verzweigten flüssigkristallinen Moleküle in den Mittelpunkt,dreiarmige Mesogene mit symmetrisch um einen Kern angeordneten Armen. Diese schlichten, aber faszinierenden Mesogene eignen sich hervorragend für das Studium von Selbstorganisationsprozessen zu komplexen, funktionalen, weichen Materialien. Die große Zahl von Diversitätselementen, der modular aufgebauten Mesogene, ermöglicht das synthetische Programmieren der sternförmigen Moleküle und die Kontrolle der Anordnung in LC Phasen, falls die Aggregationsprozesse völlig verstanden werden. Die kürzlich vorgestellten ABC-Kerne erlauben die Synthese von unsymmetrischen Mesogenen und folglich die Umsetzung des Konzepts der multifunktionalen Materialien mit definierten Nanostrukturen. In diesem Artikel wird diese außergewöhnliche Mesogenfamilie klassifiziert und deren besondere Struktur und Selbstorganisation diskutiert. Schließlich werden mögliche Anwendungen vorgestellt, für die diese Art der Mesogene vorteilhaft sein kann. [source]

Thermally Responsive Supramolecular Nanomeshes for On/Off Switching of the Rotary Motion of F1 -ATPase at the Single-Molecule Level

CHEMISTRY - A EUROPEAN JOURNAL, Issue 6 2008
Satoshi Yamaguchi Dr.
Abstract The artificial regulation of protein functions is essential for the realization of protein-based soft devices, because of their unique functions conducted within a nano-sized molecular space. We report that self-assembled nanomeshes comprising heat-responsive supramolecular hydrogel fibers can control the rotary motion of an enzyme-based biomotor (F1 -ATPase) in an on/off manner at the single-molecule level. Direct observation of the interaction of the supramolecular fibers with a microbead unit tethered to the F1 -ATPase and the clear threshold in the size of the bead required to stop ATPase rotation indicates that the bead was physically blocked so as to stop the rotary motion of ATPase. The temperature-induced formation and collapse of the supramolecular nanomesh can produce or destroy, respectively, the physical obstacle for ATPase so as to control the ATPase motion in an off/on manner. Furthermore, this switching of the F1 -ATPase motion could be spatially restricted by using a microheating device. The integration of biomolecules and hard materials, interfaced with intelligent soft materials such as supramolecular hydrogels, is promising for the development of novel semi-synthetic nano-biodevices. [source]