The calculation of hamaker constants from liftshitz theory with applications to wetting phenomena

Hough, D.B.; White, Lee R.

doi:10.1016/0001-8686(80)80006-6

Cited by 736 publications

(551 citation statements)

References 33 publications

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“…For most inorganic materials, only two undamped oscillators are commonly used to describe the whole dielectric function [37,38]:…”

Section: Torque In Vacuummentioning

confidence: 99%

“…The two oscillator model does not always provide a complete description of the dielectric properties of materials; however, in spite of its simplicity, when applied to dispersion effects it usually leads to rather precise results [37,38]. We have thus used this model for our calculations.…”

Section: Torque In Vacuummentioning

confidence: 99%

“…The parameters that determine the dielectric properties of quartz, calcite, and BaTiO 3 in the limit of the two oscillator model (equation 3.2) are listed in table I [37,38]. Figure 2 shows the calculated ǫ(iξ).…”

Section: Torque In Vacuummentioning

confidence: 99%

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Torque on birefringent plates induced by quantum fluctuations

et al. 2005

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We present detailed numerical calculations of the mechanical torque induced by quantum fluctuations on two parallel birefringent plates with in plane optical anisotropy, separated by either vacuum or a liquid (ethanol). The torque is found to vary as sin (2θ), where θ represents the angle between the two optical axes, and its magnitude rapidly increases with decreasing plate separation d. For a 40 µm diameter disk, made out of either quartz or calcite, kept parallel to a Barium Titanate plate at d ≃ 100 nm, the maximum torque (at θ = π 4 ) is of the order of ≃ 10 −19 N·m. We propose an experiment to observe this torque when the Barium Titanate plate is immersed in ethanol and the other birefringent disk is placed on top of it. In this case the retarded van der Waals (or Casimir-Lifshitz) force between the two birefringent slabs is repulsive. The disk would float parallel to the plate at a distance where its net weight is counterbalanced by the retarded van der Waals repulsion, free to rotate in response to very small driving torques.

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“…For most inorganic materials, only two undamped oscillators are commonly used to describe the whole dielectric function [37,38]:…”

Section: Torque In Vacuummentioning

confidence: 99%

Section: Torque In Vacuummentioning

confidence: 99%

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Torque on birefringent plates induced by quantum fluctuations

et al. 2005

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“…, ђ is plan 6) should res c free energy o tact was mai lecule number to attain d= henever the acts are consid ry are eliminat n of interaction e eventually iso ation distance he Hamaker co ∆ A 132 for the in quid can be c hesion between air-wise addit or by the macro ng atoms rem ation computin se of highly d for instance, ant [13]. mic structures in certain cas e considered croscopic bod lectric permi culations.Diel polarizability he constant a maker coeffic e interactions h ial [13].…”

Section: Introduction He World Health Organization (Who) Declared mentioning

confidence: 99%

“…mic structures in certain cas e considered croscopic bod lectric permi culations.Diel polarizability he constant a maker coeffic e interactions h ial [13]. ry, the Hama same laboratory with proper safety measures to avoid being infected.…”

Section: Introduction He World Health Organization (Who) Declared mentioning

confidence: 99%

Surface Thermodynamics Approach to Mycobacterium tuberculosis (MTB) – Human Sputum Interactions

JL¹,

CH²

2015

J Bioengineer & Biomedical Sci

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Abstract-This research work presents the surface thermodynamics approach to M-TB/HIV-Human sputum interactions. This involved the use of the Hamaker coefficient concept as a surface energetics tool in determining the interaction processes, with the surface interfacial energies explained using van der Waals concept of particle interactions. The Lifshitz derivation for van der Waals forces was applied as an alternative to the contact angle approach which has been widely used in other biological systems. The methodology involved taking sputum samples from twenty infected persons and from twenty uninfected persons for absorbance measurement using a digital Ultraviolet visible Spectrophotometer. The variables required for the computations with the Lifshitz formula were derived from the absorbance data. The Matlab software tools were used in the mathematical analysis of the data produced from the experiments (absorbance values). The Hamaker constants and the combined Hamaker coefficients were obtained using the values of the dielectric constant together with the Lifshitz Equation. The absolute combined Hamaker coefficients A 132abs and A 131abs on both infected and uninfected sputum samples gave the values of A 132abs = 0.21631x10Joule for M-TB infected sputum and Ã 132abs = 0.18825x10Joule for M-TB/HIV infected sputum. The significance of this result is the positive value of the absolute combined Hamaker coefficient which suggests the existence of net positive van der waals forces demonstrating an attraction between the bacteria and the macrophage. This however, implies that infection can occur. It was also shown that in the presence of HIV, the interaction energy is reduced by 13% conforming adverse effects observed in HIV patients suffering from tuberculosis.

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Dynamic ultrafiltration model for proteins: A colloidal interaction approach

Bowen¹,

Williams²

1996

Biotechnol. Bioeng.

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The calculation of hamaker constants from liftshitz theory with applications to wetting phenomena

Cited by 736 publications

References 33 publications

Torque on birefringent plates induced by quantum fluctuations

Torque on birefringent plates induced by quantum fluctuations

Surface Thermodynamics Approach to Mycobacterium tuberculosis (MTB) – Human Sputum Interactions

Dynamic ultrafiltration model for proteins: A colloidal interaction approach

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