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Schlesener, F.; Hanke, Andreas; Dietrich, S.

doi:10.1023/a:1022184508016

Cited by 106 publications

(190 citation statements)

References 65 publications

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“…Recent experiments [33] have confirmed corresponding theoretical predictions for the plate geometry [34]. For curved surfaces the critical Casimir force plays an important role in the flocculation of colloidal particles suspended in a solvent undergoing a continuous phase transition [35]. In the present context the free energy of the critical medium depends on the opening angle γ; its derivative with respect to γ amounts to the critical Casimir torque acting on the sides of the wedge or ridge.…”

Section: Introductionsupporting

confidence: 60%

Critical adsorption and Casimir torque in wedges and at ridges

Palágyi

Dietrich

2004

Phys. Rev. E

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Geometrical structures of confining surfaces profoundly influence the adsorption of fluids upon approaching a critical point Tc in their bulk phase diagram, i.e., for t = (T −Tc)/Tc → ±0. Guided by general scaling considerations, we calculate, within mean-field theory, the temperature dependence of the order parameter profile in a wedge with opening angle γ < π and close to a ridge (γ > π) for T ≷ Tc and in the presence of surface fields. For a suitably defined reduced excess adsorption Γ±(γ, t → ±0) ∼ Γ±(γ)|t| β−2ν we compute the universal amplitudes Γ±(γ), which diverge as Γ±(γ → 0) ∼ 1/γ for small opening angles, vary linearly close to γ = π for γ < π, and increase exponentially for γ → 2π. There is evidence that, within mean-field theory, the ratio Γ+(γ)/Γ−(γ) is independent of γ. We also discuss the critical Casimir torque acting on the sides of the wedge as a function of the opening angle and temperature.

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Section: Introductionsupporting

confidence: 60%

Critical adsorption and Casimir torque in wedges and at ridges

Palágyi

Dietrich

2004

Phys. Rev. E

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“…[22,23,41]) and the distance H from the center of the particle to the wall (used, e.g., in Refs. [44,46,47,48,49]), see Fig.…”

Section: Modelmentioning

confidence: 99%

“…[6,7,8,9,10,11,12,13,14,15,16,17] and references therein) or by chemically patterned [18] or geometrically structured substrates [19], as well as on spherical colloidal particles (see, e.g., Refs. [20,21,22,23] and references therein). Strong experimental evidences for critical Casimir forces have been obtained by studying wetting films near critical end points of quantum [24,25,26] or classical fluids [27,28].…”

Section: Introductionmentioning

confidence: 99%

Critical Casimir interaction of ellipsoidal colloids with a planar wall

Kondrat

Harnau

Dietrich

2009

The Journal of Chemical Physics

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Based on renormalization group concepts and explicit mean field calculations we study the universal contribution to the effective force and torque acting on an ellipsoidal colloidal particle which is dissolved in a critical fluid and is close to a homogeneous planar substrate. At the same closest distance between the substrate and the surface of the particle, the ellipsoidal particle prefers an orientation parallel to the substrate and the magnitude of the fluctuation induced force is larger than if the orientation of the particle is perpendicular to the substrate. The sign of the critical torque acting on the ellipsoidal particle depends on the type of boundary conditions for the order parameter at the particle and substrate surfaces, and on the pivot with respect to which the particle rotates.

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“…The critical Casimir effect in colloidal suspensions has attracted numerous theoretical investigations [27][28][29][30][31] due to the wide use of colloids in applications and due to their property as a paradigmatic soft matter model. Using colloids, critical Casimir forces have been measured directly by monitoring the position of a single spherical colloidal particle immersed in a binary liquid mixture of water and 2,6-lutidine and close to chemically homogeneous substrates [1,32,33].…”

Section: Introductionmentioning

confidence: 99%

Alignment of cylindrical colloids near chemically patterned substrates induced by critical Casimir torques

et al. 2014

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Recent experiments have demonstrated a fluctuation-induced lateral trapping of spherical colloidal particles immersed in a binary liquid mixture near its critical demixing point and exposed to chemically patterned substrates. Inspired by these experiments, we study this kind of effective interaction, known as the critical Casimir effect, for elongated colloids of cylindrical shape. This adds orientational degrees of freedom. When the colloidal particles are close to a chemically structured substrate, a critical Casimir torque acting on the colloids emerges. We calculate this torque on the basis of the Derjaguin approximation. The range of validity of the latter is assessed via mean-field theory. This assessment shows that the Derjaguin approximation is reliable in experimentally relevant regimes, so that we extend it to Janus particles endowed with opposing adsorption preferences. Our analysis indicates that critical Casimir interactions are capable of achieving well-defined, reversible alignments both of chemically homogeneous and of Janus cylinders.

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Cited by 106 publications

References 65 publications

Critical adsorption and Casimir torque in wedges and at ridges

Critical adsorption and Casimir torque in wedges and at ridges

Critical Casimir interaction of ellipsoidal colloids with a planar wall

Alignment of cylindrical colloids near chemically patterned substrates induced by critical Casimir torques

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