Application of the Lifshitz Theory to the Calculation of Van der Waals Forces across Thin Lipid Films

Nature ◽  
1969 ◽  
Vol 224 (5225) ◽  
pp. 1197-1198 ◽  
Author(s):  
V. A. PARSEGIAN ◽  
B. W. NINHAM
Keyword(s):  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Lipid Films ◽  
Lifshitz Theory

Van der Waals forces in oil–water systems from the study of thin lipid films - I. Measurement of the contact angle and the estimation of the van der Waals free energy of thinning of a film

1975 ◽  
Vol 347 (1649) ◽  
pp. 141-159 ◽  
Keyword(s):  
Free Energy ◽  
Van Der Waals ◽  
Monochromatic Light ◽  
Van Der Waals Forces ◽  
Contact Angles ◽  
Steric Interaction ◽  
Isotropic Layer ◽  
Free Energies ◽  
Lipid Film ◽  
Lipid Films

Free energies of formation of ‘black’ lipid films have been determined from measurements of their contact angles. The contact angles were calculated from the interference fringes formed in monochromatic light reflected from either the Plateau–Gibbs border or from lenses of bulk lipid solution trapped in the films. It is concluded that the electrostatic repulsion between the two surfaces of a film is negligibly small and that the ‘ steric’ interaction between the adsorbed monolayers of lipid molecules is of such short range that the free energy change during film formation originates almost entirely from work done by the van der Waals forces. The free energies determined for a range of different films all agree to within a factor of three with the free energy calculated from Lifshitz theory for water phases interacting across an isotropic layer of liquid hydrocarbon. Nevertheless, a systematic trend in the experimental data suggests that this picture of the lipid film is too simple and that either the polar groups of the lipid or the structure of the hydrocarbon region (or both) of the film have a significant influence on the results.

scholarly journals Calculation of Hamaker Constants in Nonaqueous Fluid Media

2000 ◽  
Vol 624 ◽  
Author(s):  
Nelson Bell ◽  
Duane Dimos
Keyword(s):  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Dielectric Materials ◽  
Van Der Waals Interactions ◽  
Experimental Measurements ◽  
Dielectric Data ◽  
Fluid Media ◽  
Lifshitz Theory ◽  
Hamaker Constants

ABSTRACTCalculations of the Hamaker constants representing the van der Waals interactions between conductor, resistor and dielectric materials are performed using Lifshitz theory. The calculation of the parameters for the Ninham-Parsegian relationship for several non-aqueous liquids has been derived based on literature dielectric data. Discussion of the role of van der Waals forces in the dispersion of particles is given for understanding paste formulation. Experimental measurements of viscosity are presented to show the role of dispersant truncation of attractive van der Waals forces

scholarly journals Calculation of Hamaker Constants in Nonaqueous Fluid Media

2000 ◽  
Vol 625 ◽  
Author(s):  
Nelson Bell ◽  
Duane Dimos
Keyword(s):  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Dielectric Materials ◽  
Van Der Waals Interactions ◽  
Experimental Measurements ◽  
Dielectric Data ◽  
Fluid Media ◽  
Lifshitz Theory ◽  
Hamaker Constants

AbstractCalculations of the Hamaker constants representing the van der Waals interactions between conductor, resistor and dielectric materials are performed using Lifshitz theory. The calculation of the parameters for the Ninham-Parsegian relationship for several non-aqueous liquids has been derived based on literature dielectric data. Discussion of the role of van der Waals forces in the dispersion of particles is given for understanding paste formulation. Experimental measurements of viscosity are presented to show the role of dispersant truncation of attractive van der Waals forces.

Contact Angles for Thin Lipid Films and the Determination of London-van der Waals Forces

Nature ◽  
1968 ◽  
Vol 217 (5130) ◽  
pp. 739-740 ◽  
Author(s):  
D. A. HAYDON ◽  
J. L. TAYLOR
Keyword(s):  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Contact Angles ◽  
Lipid Films

Self-Assembly of a Chiral Cubic Three-Connected Net from the High Symmetry Molecules C60 and SnI4

2020 ◽  
Author(s):  
Daniel B. Straus ◽  
Robert J. Cava
Keyword(s):  
Organic Synthesis ◽  
Self Assembly ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
High Symmetry ◽  
Molecular Chirality ◽  
Chiral Materials ◽  
Self Assembled ◽  
Chiral Centers

The design of new chiral materials usually requires stereoselective organic synthesis to create molecules with chiral centers. Less commonly, achiral molecules can self-assemble into chiral materials, despite the absence of intrinsic molecular chirality. Here, we demonstrate the assembly of high-symmetry molecules into a chiral van der Waals structure by synthesizing crystals of C<sub>60</sub>(SnI<sub>4</sub>)<sub>2</sub> from icosahedral buckminsterfullerene (C<sub>60</sub>) and tetrahedral SnI4 molecules through spontaneous self-assembly. The SnI<sub>4</sub> tetrahedra template the Sn atoms into a chiral cubic three-connected net of the SrSi<sub>2</sub> type that is held together by van der Waals forces. Our results represent the remarkable emergence of a self-assembled chiral material from two of the most highly symmetric molecules, demonstrating that almost any molecular, nanocrystalline, or engineered precursor can be considered when designing chiral assemblies.

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