Virial coefficients of anisotropic hard solids of revolution: The detailed influence of the particle geometry

Herold, Elisabeth; Hellmann, Robert; Wagner, Joachim

doi:10.1063/1.5004687

Cited by 17 publications

(3 citation statements)

References 35 publications

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“…These hard-particle virial coefficients are expected to increase with the volume of the particle, here determined by L . Comparing with theoretical calculations for hard spherocylinders, 64 there is expected to be a L 2 dependence, as appears to be the case in Figure 6 . Second virial coefficients for cylinders with various aspect ratios as a function of the interaction strength, βϵ , are shown in Figure 7 .…”

Section: Second Virial Coefficientsupporting

confidence: 55%

Monte Carlo simulation of cylinders with short-range attractions

et al. 2018

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Cylindrical or rod-like particles are promising materials for the applications of fillers in nanocomposite materials and additives to control rheological properties of colloidal suspensions. Recent advances in particle synthesis allows for cylinders to be manufactured with short-ranged attractions to study the gelation as a function of packing fraction, aspect ratio and attraction strength. In order to aid in the analysis of small-angle scattering experiments of rod-like particles, computer simulation methods were used to model these particles with specialized Monte Carlo algorithms and tabular superquadric potentials. The attractive interaction between neighboring rods increases with the amount of locally-accessible surface area, thus leading to patchy-like interactions. We characterize the clustering and percolation of cylinders as the attractive interaction increases from the homogenous fluid at relatively low attraction strength, for a variety of aspect ratios and packing fractions. Comparisons with the experimental scattering results are also presented, which are in agreement.

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Section: Second Virial Coefficientsupporting

confidence: 55%

Monte Carlo simulation of cylinders with short-range attractions

et al. 2018

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“…We consider a collection of N c hard superballs in a volume V , each superball having a volume v sb , surface area s sb and surface integrated mean curvature [31] c sb . The second virial coefficient (B 2 ) for hard particles is given by the orientationally averaged excluded volume between two particles [32], and for a suspension of monodisperse convex particles (hence for superballs with m ≥ 2) in a fluid state reads [33,34]…”

Section: Fluid Statementioning

confidence: 99%

Phase behaviour of colloidal superballs mixed with non-adsorbing polymers

2018

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Inspired by experimental work on colloidal cuboid-polymer dispersions (Rossi et al., Soft Matter, 7, 4139 (2011)) we have theoretically studied the phase behaviour of such mixtures. To that end, free volume theory (FVT) was applied to predict the phase behaviour of mixtures of superballs and non-adsorbing polymer chains in a common solvent. Closed expressions for the thermodynamic properties of a suspension of hard colloidal superballs have been derived, accounting for fluid (F), face-centred cubic (FCC) and simple cubic (SC) phase states. Even though the considered solid phases are approximate, the hard superballs phase diagram semi-quantitatively matches with more evolved methods. The theory developed for the cuboid-polymer mixture reveals a rich phase behaviour, which includes not only isostructural F-F coexistence, but also SC-SC coexistence, several triple coexistences, and even a quadruple-phase coexistence region (F-F-SC-FCC). The model proposed offers a tool to asses the stability of cuboid-polymer mixtures in terms of the colloid-to-polymer size ratio.

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“…However, despite a fairly common practice to analyze molecular interactions by means of virial coefficients, − there is no quantitative relationship between the intermolecular interaction potential and the virial coefficients with the order higher than the second one, A 2 . The second virial coefficient A 2 can be determined by means of the total pair interaction potential W , defined within the McMillan–Mayer theory for cylindrical particles as ,,− , where a 1 0 is the activity of the pure solvent, k B is the Boltzmann constant, T is the temperature, r is the interprotein center-to-center distance, and a is the particle radius. The lower integration limit is taken as 2( a + d ) + δ where d is the thickness of the surface charge layer and δ is the thickness of the protein bound water layer, which is usually chosen to be 3 Å …”

Section: Introductionmentioning

confidence: 99%

The Role of pH and Ionic Strength in the Attraction–Repulsion Balance of Fibrinogen Interactions

2021

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Fibrinogen (Fg) self-assembly is sensitive to the physicochemical properties of an environment like pH and ionic strength. These parameters tune the direction and strength of noncovalent physical driving forces determining protein intermolecular interactions. The attraction–repulsion balance in intermolecular interactions of the multidomain protein Fg at pH values 3.5, 7.4, and 9.5 and varying ionic strengths of the water medium has been analyzed by the complex diffusive approach, proposed by us previously. The concentration dependence of protein collective diffusion was analyzed within the phenomenological approach, based on the frictional formalism of nonequilibrium thermodynamics proposed by H. Vink. The analysis of protein diffusion data has shown the fundamental difference in the physical nature and direction of interaction forces between protein molecules at different conditions. The paired interaction potential of protein molecules was characterized in terms of second virial coefficients and Hamaker constants within the Deryaguin–Landau–Verwey–Overbeek theory and the “porous” colloid particle model. Our results indicated the maximum Hamaker constant and dominance of the van der Waals attraction between Fg molecules at pH 7.4. The increase in pH up to 9.5 results in the zero values of the second virial coefficient and Hamaker constant, corresponding to the full reciprocal compensation for electrostatic repulsion and van der Waals attraction. In the acidic medium (pH 3.5), the strong electrostatic repulsion substantially exceeds the van der Waals attraction. A high ionic strength is characterized by a significant decrease of all intermolecular interactions, which is expressed in almost zero values of virial coefficients and the Hamaker constant. Thus, it is experimentally shown that the physiological conditions of the Fg environment (pH 7.4 and slight ionic strength) provide a high probability for peak physical attraction between fibrinogen molecules, which is used in nature to facilitate blood clotting.

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Virial coefficients of anisotropic hard solids of revolution: The detailed influence of the particle geometry

Cited by 17 publications

References 35 publications

Monte Carlo simulation of cylinders with short-range attractions

Monte Carlo simulation of cylinders with short-range attractions

Phase behaviour of colloidal superballs mixed with non-adsorbing polymers

The Role of pH and Ionic Strength in the Attraction–Repulsion Balance of Fibrinogen Interactions

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