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Showing papers on "Phase (matter) published in 2004"


Journal ArticleDOI
TL;DR: In this paper, it was shown that the confusion principle does not apply, and other factors are more important in promoting glass formation of late transition metal rich multicomponent alloys.
Abstract: Multicomponent alloys containing several components in equal atomic proportions have been manufactured by casting and melt spinning, and their microstructures and properties have been investigated by a combination of optical microscopy, scanning electron microscopy, electron probe microanalysis, X-ray diffractrometry and microhardness measurements. Alloys containing 16 and 20 components in equal proportions are multiphase, crystalline and brittle both as-cast and after melt spinning. A five component Fe20Cr20Mn20Ni20Co20 alloy forms a single fcc solid solution which solidifies dendritically. A wide range of other six to nine component late transition metal rich multicomponent alloys exhibit the same majority fcc primary dendritic phase, which can dissolve substantial amounts of other transition metals such as Nb, Ti and V. More electronegative elements such as Cu and Ge are less stable in the fcc dendrites and are rejected into the interdendritic regions. The total number of phases is always well below the maximum equilibrium number allowed by the Gibbs phase rule, and even further below the maximum number allowed under non-equilibrium solidification conditions. Glassy structures are not formed by casting or melt spinning of late transition metal rich multicomponent alloys, indicating that the confusion principle does not apply, and other factors are more important in promoting glass formation.

5,289 citations


Journal ArticleDOI
TL;DR: In this article, a morphotropic phase boundary between orthorhombic and tetragonal phases is found in the composition range 0.05
Abstract: Lead-free piezoelectric ceramics (1−x)(Na0.5K0.5)NbO3–xLiNbO3 {[Lix(Na0.5K0.5)1−x]NbO3} (x=0.04–0.20) have been synthesized by an ordinary sintering technique. The materials with perovskite structure is orthorhombic phase at x⩽0.05 and becomes tetragonal phase at x⩾0.07, a phase K3Li2Nb5O15 with tetragonal tungsten bronze structure begins to appear at x=0.08 and becomes dominant with increasing the content of LiNbO3. A morphotropic phase boundary between orthorhombic and tetragonal phases is found in the composition range 0.05

1,354 citations


Journal ArticleDOI
TL;DR: The structure of the concentrated polymer phase seems to resemble a continuous polymer phase in which the protein can diffuse around, as well as the individual polysaccharide molecules, which resembles the behaviour of a (viscous) concentrated particle dispersion.
Abstract: Coacervation of proteins and anionic polysaccharides is both of practical and theoretical interest. From a large body of literature, it seems that the phase separation is mainly entropically driven, and may most probably be attributed to the delocalisation of the counter ions of the protein and the polysaccharide. The protein and polysaccharide appear to form complexes in solution, which can be viewed as new colloidal entities. These complex particles are neutral and exhibit an attractive interaction, which leads to a phase separation of the gas-liquid type in which a (very) dilute colloidal phase coexists with a very concentrated colloidal phase. In the case of strong poly-acids, usually, a precipitate is formed rather than a liquid coacervate phase. The structure of the concentrated polymer phase seems to resemble a continuous polymer phase in which the protein can diffuse around, as well as the individual polysaccharide molecules. Time scales of diffusion vary from milliseconds to days depending on the strength of the interaction. From a rheological point of view, the concentrated phase is much more viscous than elastic and the rheology resembles the behaviour of a (viscous) concentrated particle dispersion. Theoretical developments are limited probably due to the difficulty to describe the (correlated) charge distribution in the system. There is a strong interest in coacervates for the use of encapsulation. For the same reason, much attention is given to replacing the traditional gelatin by milk and plant proteins.

1,000 citations


Journal ArticleDOI
TL;DR: This phase of emulsion optimisation represents an important step in the process of polymeric nanocapsules preparation using nanoprecipitation or interfacial polycondensation combined with spontaneous emulsification technique.

772 citations


Journal ArticleDOI
TL;DR: The polymeric nitrogen with the theoretically predicted cubic gauche structure (cg-N) represents a new class of single-bonded nitrogen materials with unique properties such as energy capacity: more than five times that of the most powerfully energetic materials.
Abstract: Nitrogen usually consists of molecules where two atoms are strongly triple-bonded. Here, we report on an allotropic form of nitrogen where all atoms are connected with single covalent bonds, similar to carbon atoms in diamond. The compound was synthesized directly from molecular nitrogen at temperatures above 2,000 K and pressures above 110 GPa using a laser-heated diamond cell. From X-ray and Raman scattering we have identified this as the long-sought-after polymeric nitrogen with the theoretically predicted cubic gauche structure (cg-N). This cubic phase has not been observed previously in any element. The phase is a stiff substance with bulk modulus >or=300 GPa, characteristic of strong covalent solids. The polymeric nitrogen is metastable, and contrasts with previously reported amorphous non-molecular nitrogen, which is most likely a mixture of small clusters of non-molecular phases. The cg-N represents a new class of single-bonded nitrogen materials with unique properties such as energy capacity: more than five times that of the most powerfully energetic materials.

716 citations


Journal ArticleDOI
TL;DR: In this paper, a family of solubility curves for poorly crystalline calcium silicate hydrate (C-S-H) phases were derived from 29Si magic-angle spinning (MAS) NMR data and by charge balance calculations.

715 citations


Journal ArticleDOI
TL;DR: In this paper, a mathematical model for lithium intercalation and phase change in an iron phosphate-based lithium-ion cell was developed to understand the cause for the low power capability of the material.
Abstract: This paper develops a mathematical model for lithium intercalation and phase change in an iron phosphate-based lithium-ion cell in order to understand the cause for the low power capability of the material. The juxtaposition of the two phases is assumed to be in the form of a shrinking core, where a shell of one phase covers a core of the second phase. Diffusion of lithium through the shell and the movement of the phase interface are described and incorporated into a porous electrode model consisting of two different particle sizes. Open-circuit measurements are used to estimate the composition ranges of the single-phase region. Model-experimental comparisons under constant current show that ohmic drops in the matrix phase, contact resistances between the current collector and the porous matrix, and transport limitations in the iron phosphate particle limit the power capability of the cells. Various design options, consisting of decreasing the ohmic drops, using smaller particles, and substituting the liquid electrolyte by a gel are explored, and their relative importance discussed. The model developed in this paper can be used as a means of optimizing the cell design to suit a particular application.

708 citations



Journal ArticleDOI
TL;DR: In this paper, the role of Y/Ln as a fluxing agent is relatively small in terms of glass formability enhancement, and the obtained bulk metallic glasses are non-ferromagnetic and exhibit high elastic moduli of approximately 180-200 GPa and microhardness of approximately 13 GPa.
Abstract: Fe–Cr–Mo–(Y,Ln)–C–B bulk metallic glasses (Ln are lanthanides) with maximum diameter thicknesses reaching 12 mm have been obtained by casting. The high glass formability is attained despite a low reduced glass transition temperature of 0.58. The inclusion of Y/Ln is motivated by the idea that elements with large atomic sizes can destabilize the competing crystalline phase, enabling the amorphous phase to be formed. It is found that the role of Y/Ln as a fluxing agent is relatively small in terms of glass formability enhancement. The obtained bulk metallic glasses are non-ferromagnetic and exhibit high elastic moduli of approximately 180–200 GPa and microhardness of approximately 13 GPa.

516 citations


Journal ArticleDOI
TL;DR: In this article, the authors review the equilibrium phase field of various Al-Mg-Si-Cu alloys, noting the many important commercial alloys that contain the Q phase as an equilibrium one.

514 citations


Journal ArticleDOI
TL;DR: High ionic conductivity for a large variety of salts dissolved in the highly polar medium based on the plastic-crystal form of succinonitrile is found, revealing a dichotomy between plastic crystals and conventional polymer media.
Abstract: The plastic-crystalline phase of succinonitrile as a universal matrix for solid-state ionic conductors

Journal ArticleDOI
TL;DR: The results reemphasize the complex phase behavior of cholesterol-containing membranes and provide a framework for interpreting (2)H-NMR experiments in similar membranes.

Journal ArticleDOI
TL;DR: The results strongly suggest that the observed ferromagnetic phase is oxygen-vacancy-stabilized Mn2−xZnxO3−δ, rather than by carrier-induced interaction between separated Mn atoms in ZnO.
Abstract: The recent discovery of ferromagnetism above room temperature in low-temperature-processed MnO2–ZnO has generated significant interest. Using suitably designed bulk and thin-film studies, we demonstrate that the ferromagnetism in this system originates in a metastable phase rather than by carrier-induced interaction between separated Mn atoms in ZnO. The ferromagnetism persists up to ∼980 K, and further heating transforms the metastable phase and kills the ferromagnetism. By studying the interface diffusion and reaction between thin-film bilayers of Mn and Zn oxides, we show that a uniform solution of Mn in ZnO does not form under low-temperature processing. Instead, a metastable ferromagnetic phase develops by Zn diffusion into the Mn oxide. Direct low-temperature film growth of Zn-incorporated Mn oxide by pulsed laser deposition shows ferromagnetism at low Zn concentration for an optimum oxygen growth pressure. Our results strongly suggest that the observed ferromagnetic phase is oxygen-vacancy-stabilized Mn2−xZnxO3−δ.

Journal ArticleDOI
TL;DR: In this article, a density functional theory study of water adsorption on metal surfaces is presented, where the water-surface interaction is dominated by the lone pair-d band coupling through the surface states and a simultaneous enhancement of hydrogen bonding is generally observed in many adsorbed structures.
Abstract: We present a density functional theory study of water adsorption on metal surfaces. Prototype water structures including monomers, clusters, one-dimensional chains, and overlayers have been investigated in detail on a model system-a Pt(111) surface. The structure, energetics, and vibrational spectra are all obtained and compared with available experimental data. This study is further extended to other metal surfaces including Ru(0001), Rh(111), Pd(111), and Au(111), where adsorption of monomers and bilayers has been investigated. From these studies, a general picture has emerged regarding the water-surface interaction, the interwater hydrogen bonding, and the wetting order of the metal surfaces. The water-surface interaction is dominated by the lone pair-d band coupling through the surface states. It is rather localized in the contacting layer. A simultaneous enhancement of hydrogen bonding is generally observed in many adsorbed structures. Some special issues such as the partial dissociation of water on Ru(0001) and in the RT39 bilayer phase, the H-up and H-down conversion, and the quantum-mechanical motions of H atoms are also discussed.

Journal ArticleDOI
TL;DR: In this paper, the authors used small-angle neutron scattering from polyethylene oxide (PEO) solutions in various deuterated solvents, and analyzed the possible causes of clustering.
Abstract: The clustering phenomenon has been observed in many macromolecular systems. Poly(ethylene oxide) solutions are characterized by a clustering effect that has been extensively discussed in the literature. Its origin has remained elusive. Using small-angle neutron scattering from PEO solutions in various deuterated solvents, the possible causes of clustering that have been given in the literature are analyzed here. These include impurities in water, possible PEO crystallization, a subtle phase transition whereby a concentrated phase coexists with free polymer coils, hydrogen-bond physical cross-linking, and finally chain ends effect. We have shown that under the experimental conditions considered here (4% PEO weight fraction) the mostly forgotten chain ends effect is at the origin of clustering in poly(ethylene oxide) solutions.

Journal ArticleDOI
TL;DR: In this article, single-walled carbon nanotubes (SWNTs) form a highly unusual nematic phase consisting of spaghetti-like self-assembled supermolecular strands of mobile, solvated tubes in equilibrium with a dilute isotropic phase.
Abstract: Single-walled carbon nanotubes (SWNTs) can be dispersed at high concentration in superacids; the protonation of SWNTs sidewalls eliminates wall-wall van der Waals interactions and promotes the dispersion process. At very low concentration, SWNTs in superacids dissolve as individual tubes which behave as Brownian rods. At higher concentration, SWNTs form a highly unusual nematic phase consisting of spaghetti-like self-assembled supermolecular strands of mobile, solvated tubes in equilibrium with a dilute isotropic phase. At even higher concentration, the spaghetti strands self-assemble into a polydomain nematic liquid crystal. Upon the introduction of small amounts of water, the liquid crystal phase separates into needle-shaped strands (20 Im long) of highly aligned SWNTs, termed alewives. Under anhydrous condition, the liquid crystalline phase can be processed into highly aligned fibers of pure SWNT without the aid of any surfactants or polymers.

Journal ArticleDOI
TL;DR: In this paper, a new method is presented to account for phase changes in a fully implicit numerical model for coupled heat transport and variably saturated water flow involving conditions both above and below zer...
Abstract: A new method is presented to account for phase changes in a fully implicit numerical model for coupled heat transport and variably saturated water flow involving conditions both above and below zer ...


Journal ArticleDOI
22 Jan 2004-Nature
TL;DR: New and re-analysed sound velocity measurements of shock-compressed iron at Earth-core conditions show that melting starts at 225±3 GPa and is complete at 260 ± 3‬GPa, both on the Hugoniot curve—the locus ofshock-compression states.
Abstract: Seismological data can yield physical properties of the Earth's core, such as its size and seismic anisotropy. A well-constrained iron phase diagram, however, is essential to determine the temperatures at core boundaries and the crystal structure of the solid inner core. To date, the iron phase diagram at high pressure has been investigated experimentally through both laser-heated diamond-anvil cell and shock-compression techniques, as well as through theoretical calculations. Despite these contributions, a consensus on the melt line or the high-pressure, high-temperature phase of iron is lacking. Here we report new and re-analysed sound velocity measurements of shock-compressed iron at Earth-core conditions. We show that melting starts at 225 +/- 3 GPa (5,100 +/- 500 K) and is complete at 260 +/- 3 GPa (6,100 +/- 500 K), both on the Hugoniot curve-the locus of shock-compressed states. This new melting pressure is lower than previously reported, and we find no evidence for a previously reported solid-solid phase transition on the Hugoniot curve near 200 GPa (ref. 16).

Journal ArticleDOI
TL;DR: In this paper, the supramolecular crystal structure in poly(vinylidene fluoride) (PVDF) solution-cast films was studied through changing crystallization conditions in two solvents of different structures and polarities.
Abstract: The supramolecular crystal structure in poly(vinylidene fluoride) (PVDF) solution-cast films is studied through changing crystallization conditions in two solvents of different structures and polarities. The crystalline-state chain conformations of isothermally solution-crystallized PVDF in N, N-dimethylacetamide (DMAc), and cyclohexanone are studied through the specific FTIR absorption bands of α, β, and γ phase crystals. There are no changes in the FTIR spectra of cyclohexanone solution-crystallized films in the temperature range of 50–120 °C. In the case of DMAc solution-crystallized films, low temperature crystallization mainly results in formation of trans states (β and γ phases), whereas at higher temperatures gauche states become more populated (α phase). This is due to the variations in solvent polarity and ability to induce a specific conformation in PVDF chains, through the changes in chain coil dimensions. This indicates that in spite of cyclohexanone solutions, the intermolecular interactions between PVDF and DMAc are temperature-sensitive and more important in stabilizing conformations of PVDF in crystalline phase than temperature dependence of PVDF chain end-to-end distance . The high-resolution 19F NMR spectroscopy also showed little displacement in PVDF characteristic chemical shifts probably due to changes in PVDF chain conformation resulting from temperature variations. Upon uniaxial stretching of the prepared films under certain conditions, contribution of trans state becomes more prominent, especially for the originally higher α phase-containing films. Due to formation of some kink bands during film stretching and phase transformation, α phase absorption bands are still present in infrared spectra. Besides, uniaxial stretching greatly enhances piezoelectric properties of the films, maybe due to formation of oriented β phase crystals, which are of more uniform distribution of dipole moments. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3487–3495, 2004

01 Mar 2004
TL;DR: In this paper, a mean-field approach is used to interpret the numerical results obtained by Monte Carlo simulations, and the phase diagram of this nonconserved dynamics in the thermodynamic limit is predicted.
Abstract: We study a one-dimensional totally asymmetric exclusion process with random particle attachments and detachments in the bulk. The resulting dynamics leads to unexpected stationary regimes for large but finite systems. Such regimes are characterized by a phase coexistence of low and high density regions separated by domain walls. We use a mean-field approach to interpret the numerical results obtained by Monte Carlo simulations, and we predict the phase diagram of this nonconserved dynamics in the thermodynamic limit.

Journal ArticleDOI
15 Jan 2004-Nature
TL;DR: In this article, it has been suggested that non-Fermi-liquid phases of metals may exist in some heavy-fermion compounds and oxide materials, but the discovery of a characteristic microscopic signature of such phases presents a major challenge.
Abstract: Only a few metallic phases have been identified in pure crystalline materials. These include normal, ferromagnetic and antiferromagnetic metals, systems with spin and charge density wave order, and superconductors. Fermi-liquid theory provides a basis for the description of all of these phases. It has been suggested that non-Fermi-liquid phases of metals may exist in some heavy-fermion compounds and oxide materials, but the discovery of a characteristic microscopic signature of such phases presents a major challenge. The transition-metal compound MnSi above a certain pressure (p(c) = 14.6 kbar) provides what may be the cleanest example of an extended non-Fermi-liquid phase in a three-dimensional metal. The bulk properties of MnSi suggest that long-range magnetic order is suppressed at p(c) (refs 7-12). Here we report neutron diffraction measurements of MnSi, revealing that sizeable quasi-static magnetic moments survive far into the non-Fermi-liquid phase. These moments are organized in an unusual pattern with partial long-range order. Our observation supports the existence of novel metallic phases with partial ordering of the conduction electrons (reminiscent of liquid crystals), as proposed for the high-temperature superconductors and heavy-fermion compounds.

Journal ArticleDOI
TL;DR: The observed unique thermochromic transition (pink solution --> blue gel-like phase) is accompanied by an exothermic peak in differential scanning calorimetry (DSC), and is shown to be an enthalpy-driven process.
Abstract: A novel class of thermally responsive supramolecular assemblies is formed from the lipophilic cobalt(II) complexes of 4-alkylated 1,2,4-triazoles. When an ether linkage is introduced in the alkylchain moiety, a blue gel-like phase is formed in chloroform, even at very low concentration (ca. 0.01 wt %, at room temperature). The blue color is accompanied by a structured absorption around 580-730 nm, which is characteristic of cobalt (II) in the tetrahedral (T(d)) coordination. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) of the gel-like phase confirms the formation of networks of fibrous nanoassemblies with widths of 5-30 nm. The observed widths are larger than a molecular length of the triazole ligand (ca. 2.2 nm) and they are consisted of aggregates of T(d) coordination polymers. Very interestingly, the blue gel-like phase turned into a solution by cooling below 25 degrees C. A pale pink solution is obtained at 0 degrees C, indicating the formation of octahedral (O(h)) complexes. The observed thermochromic transition is totally reversible. The formation of gel-like networks by heating is contrary to the conventional organogels, which dissolve upon heating. Temperature dependence of the storage and loss moduli (G' and G") shows minima around at 27 degrees C, at which temperature they gave comparable values. On the other hand, G' exceeds G" both in the gel-like phase (temperature above 27 degrees C) and in the solution phase (temperature below 25 degrees C). These observations indicate that T(d) complexes are present as low-molecular weight species around at 25-27 degrees C. They are self-assembled to polymeric T(d) complexes by heating and form gel-like networks. Upon cooling the solution below 25 degrees C, T(d) complexes are converted to O(h) complexes and they also self-assemble into oligomeric or polymeric species at lower temperatures. The observed unique thermochromic transition (pink solution --> blue gel-like phase) is accompanied by an exothermic peak in differential scanning calorimetry (DSC), and is shown to be an enthalpy-driven process. The lipophilic modification of one-dimensional coordination systems provides unique solution properties and it would be widely applicable to the design of thermoresponsive, self-assembling molecular wires.

Journal ArticleDOI
01 Nov 2004-Methods
TL;DR: Methods to determine the phase diagram of an aqueous solution of a globular protein are described, focusing on the solid (crystal) and condensed liquid states.

Proceedings ArticleDOI
13 Dec 2004
TL;DR: In this paper, the chalcogenide phase-change mechanism and phase distribution in the programmed cell is studied by both experiments and a numerical model, which self-consistently addresses the electrical-thermal conduction phase transition.
Abstract: We analyzed the programming dynamics in phase-change memory (PCM) cells. The chalcogenide phase-change mechanism and phase distribution in the programmed cell is studied by both experiments and a numerical model, which self-consistently addresses the electrical-thermal conduction phase transition. We show that the reset-set transition is strongly coupled to the electronic switching in the amorphous phase, thus supporting the need for a self-consistent electrothermal-phase transition model to correctly account for all experimental evidences.

Journal ArticleDOI
TL;DR: In this article, phase separation in polyfluorene-based electroluminescent polymer blends consisting of poly(2,7-(9,9-di-n-octylfluorene)-alt-benzothiadiazole) (F8BT) and poly( 2,7(9, 9-di)-n-orthogonal poly(1,4)-phenylene-((4-sec-butylphenyl)imino)-1, 4-phenylene)) (TFB)) is studied.
Abstract: We have studied phase separation in polyfluorene-based electroluminescent polymer blends consisting of poly(2,7-(9,9-di-n-octylfluorene-alt-benzothiadiazole) (F8BT) and poly(2,7-(9,9-di-n-octylfluorene)-alt-(1,4-phenylene-((4-sec-butylphenyl)imino)-1,4-phenylene)) (TFB). We present detailed studies on spin-cast thin-film morphology of the blends, using micro-Raman spectroscopy and X-ray photoelectron spectroscopy. Micron-scale lateral phase separation is observed in these blend thin films. However, these phase-separated domains are not pure at the submicron length scale, and a nanoscale vertical phase segregation occurs with enrichment of the lower surface energy component (TFB) at both air and substrate interfaces. Imaging of the spatial uniformity of electroluminescence emission on the microscopic scale indicates spatially localised charge-carrier recombination in light-emitting diodes (LEDs) fabricated with these blends. On the basis of these studies, we propose a model for the development of thin-film...

Journal ArticleDOI
TL;DR: It is demonstrated that polymeric self-assembly, reversibility of hydrogen bonding, and polymer–additive phase behaviour allow temperature response in the solid state with large and reversible switching of an optical bandgap.
Abstract: In aqueous solutions the response of polymers and biological matter to external conditions, such as temperature and pH, is typically based on the hydrophobic/hydrophilic balance and its effects on the polymer conformation. In the solid state, related concepts using competing interactions could allow novel functions. In this work we demonstrate that polymeric self-assembly, reversibility of hydrogen bonding, and polymer-additive phase behaviour allow temperature response in the solid state with large and reversible switching of an optical bandgap. A complex of polystyrene-block-poly(4-vinylpyridinium methanesulphonate) and 3-n-pentadecylphenol leads to the supramolecular comb-shaped architecture with a particularly long lamellar period. The sample is green at room temperature, as an incomplete photonic bandgap due to a dielectric reflector is formed. On heating, hydrogen bonds are broken and 3-n-pentadecylphenol additionally becomes soluble in polystyrene, leading to a sharp and reversible transition at approximately 125 degrees C to uncoloured material due to collapse of the long period. This encourages further developments, for example, for functional coatings or sensors in the solid state.

Journal ArticleDOI
TL;DR: In this paper, a detailed study of the photoluminescence from thin films of thin poly(9,9-dioctylfluorene) containing different fractions of planarized (β-phase) chains within the glassy polymer film was performed.
Abstract: We have performed a detailed study of the photoluminescence from thin films of blue-light-emitting poly(9,9-dioctylfluorene) containing different fractions of planarized (β-phase) chains within the glassy polymer film. Bychoosing solvents with a range of polarities and boiling points we were able to cast films with reliable control of the relative amounts of β-phase chains present. We analyzed the emission spectra in terms of Franck-Condon progressions and found that, at low temperatures (8 K), the lumineseence can be modeled accurately by considering two distinct contributions from the two phases present in the film. The Huang-Rhys parameter for the β phase is shown to be approximately half the value obtained for the glassy phase, in agreement with a more delocalized exciton in the β phase. Time-resolved photoluminescence measurements on a film containing roughly 25% of β phase reveal a fast transfer of excitations from the glassy to the β phase, indicating that the two phases are well intermixed. Assuming the transfer dynamics to be governed by dipole-dipole coupling, we obtain a Forster radius of 8.2′0.6 nm, significantly larger than the radius typically found for excitation transfer within the glassy phase. These results are consistent with the large spectral overlap between the emission of the glassy phase and the absorption of the β phase and explain why the latter dominates the emission even from films containing only a small fraction of β-phase chains.

Journal ArticleDOI
TL;DR: In this paper, the utility of temperature-induced volume phase transitions in controlling the crystallization and melting of colloidal crystals has been discussed, and it is proposed that multiple weak attractive interactions between particles can drive crystallization at particle concentrations well below the hard-sphere freezing point.
Abstract: Colloidal crystals assembled from stimuli-sensitive hydrogel particles composed largely of the thermoresponsive polymer poly(N-isopropylacrylamide) display unusual phase behavior because of the inherent “softness” of their interaction potentials as well as the particle thermoresponsivity In this contribution, we review results from our group that illustrate the use of such soft-sphere building blocks in the construction of colloidal crystals First, we describe the utility of temperature-induced volume phase transitions in controlling the crystallization and melting of the colloidal crystals These methods then enable the study of the complex phase behavior of certain types of microgels For example, it is proposed that multiple weak attractive interactions between particles can drive crystallization at particle concentrations well below the hard-sphere freezing point Finally, the utility of soft-sphere crystals in the development of new photonic materials is presented in examples of laser direct writin

Journal ArticleDOI
TL;DR: In this paper, an Eulerian two-fluid model for the prediction of dispersed two-phase (gas/liquid and liquid/liquid) flow at high volume fractions of the dispersed phase is presented.