A Multipurpose Instrument To Measure the Vitreous Properties of Charged Colloidal Solids

Schöpe, Hans Joachim; Palberg, Thomas

doi:10.1006/jcis.2000.7258

Cited by 30 publications

(38 citation statements)

References 50 publications

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“…Shearing elasticity of colloidal crystal samples was probed by TRS [17]. The cylindrical sample cell was put into oscillations with very low amplitude around its vertical axis.…”

Section: Shear Modulus Determinationmentioning

confidence: 99%

“…In this respect the elasticity of the colloidal crystals has been studied in recent years both experimentally and theoretically [10][11][12][13][14]. Experimentally, shear elastic moduli of the colloidal crystals are usually measured through the method of torsional resonance spectroscopy (TRS) in which standing waves are excited when rotary oscillations are imposed on the colloidal crystals [15][16][17]. In the aspect of theoretical studies, general equations between two-body interatomic potentials in a lattice model and elastic constants were derived for monoatomic solids [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

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Effect of void structures in crystalline structure on the shear moduli of charged colloidal crystals

Wang

Zhou

et al. 2017

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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h i g h l i g h t s• Inconsistencies between the theoretical and experimental results for shear moduli are attributed to defects in real crystals.• Modifications include considering the effect of void structures and using Sogami-Ise potential.• Modified model is verified by good consistency between theoretical values and experimental results. t r a c tThe existing theoretical model relating shear modulus to inter-particle interaction potential always significantly overestimates the modulus compared with its experimental value for colloidal crystal formed by highly-charged particles. We suppose that such huge disagreements between the theoretical and experimental results are due to that the theoretical model is derived from perfect crystalline structures. To modify the theoretical model, the effect of void defects is introduced to the model and the SogamiIse potential model is adopted instead of the commonly used Yukawa potential model. It is shown that with these two modifications the shear modulus model produces results much more consistent with the experimental ones.

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“…Shearing elasticity of colloidal crystal samples was probed by TRS [17]. The cylindrical sample cell was put into oscillations with very low amplitude around its vertical axis.…”

Section: Shear Modulus Determinationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of void structures in crystalline structure on the shear moduli of charged colloidal crystals

Wang

Zhou

et al. 2017

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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“…Long range order is lost for PTFE180 at n 35 lm )3 . As the elasticity data (sensitive to the local neighbourhood of a particle [23]) are well described by a single theoretical curve, the observed short-range order remains of bcc structure.…”

Section: Resultsmentioning

confidence: 80%

“…Details of the novel two-arm light scattering goniometer with counterpropagating illumination and three independent detection schemes are given elsewhere [23,24].…”

Section: Crystal Nucleation Versus Vitri®cation In Charged Colloidal mentioning

confidence: 99%

Crystal nucleation versus vitrification in charged colloidal suspensions

Schöpe

Palberg

Trends in Colloid and Interface Science XV

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“…It uses two counterpropagating illumination/detection schemes for static and dynamic light scattering and a third independently adjustable scheme for the torsional resonance detection. Details have recently been given elsewhere [11].…”

Section: Introductionmentioning

confidence: 99%

Properties of mixed colloidal crystals

Wette

Schöpe

Palberg

Trends in Colloid and Interface Science XV

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IntroductionColloidal crystals are the subject of intense research for several reasons. First, owing to their speci®c length and time scales their properties are readily accessible by various forms of light scattering and microscopy. Second, a number of interesting questions of fundamental interest in condensed matter physics can be addressed in a well-de®ned model systems. This concerns both equilibrium properties (like diusive dynamics, structure or phase behaviour), response to external ®elds (like electrokinetic properties or sedimentation) and situations far from equilibrium (like the glass transition, shear-melting or crystallisation kinetics). Third, however, important applications may also result from a better understanding of the generic properties. Optical-band-gap materials are one of these.Recently focus has shifted from single-component suspensions to mixtures. The most prominent examples deal with hard-sphere or hard-sphere-polymer mixtures of large size dierence, where phase separation is observed owing to attractive terms in the potential of the mean force [1,2]. Much less is known about charged mixtures. Only a few reports exist on the phase behaviour [3,4,5], and fewer on even other properties, like shear rigidity [6], diusion [7,8] or crystallisation kinetics.We report on a mixture of two species of polystyrene latex spheres in deionised aqueous suspension. Their size ratio is C 0.85. Such a small value should not induce an entropically driven instability. Nevertheless, the phase behaviour is not immediately obvious. The formation of alloy structures of glasses or of precipitats can be expected. Alloys may either be compositionally ordered (e.g. of NaCl structure) or disordered (e.g. Cu/Au). We conducted a number of dierent experiments to comprehensively characterise the resulting solids. Besides the static structure factor, S(q), we also measured the conductivity, r, and the static shear modulus, G. The former is very sensitive to the formation of precipitates; the latter has been shown to yield valuable information about the local crystal structure [9]. Finally, we also report some of the ®rst dynamic light scattering measurements on polycrystalline samples. Their interpretation can be qualitative only, since a rigorous scattering theory of such nonergodic and inhomogeneous materials is still demanded. The combination of our results shows that at low-to-intermediate particle concentrations randomly substituted alloys of body-centered-cubic (bcc) structure are formed.Abstract We prepared colloidal crystals from aqueous suspensions of spherical, charged polystyrene spheres under deionised conditions. Using a home-built multipurpose light scattering apparatus we measured the static structure factor, the static shear modulus and the intermediate scattering function. In addition we also monitored also the conductivity as a function of the composition and the particle number density. For the mixture investigated the data are well described assuming the formation of randomly substituted body-centere...

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A Multipurpose Instrument To Measure the Vitreous Properties of Charged Colloidal Solids

Cited by 30 publications

References 50 publications

Effect of void structures in crystalline structure on the shear moduli of charged colloidal crystals

Effect of void structures in crystalline structure on the shear moduli of charged colloidal crystals

Crystal nucleation versus vitrification in charged colloidal suspensions

Properties of mixed colloidal crystals

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