van der Waals forces

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van der Waals forc·es

(von der vahls),
first postulated by van der Waals in 1873 to explain deviations from ideal gas behavior seen in real gases; the attractive forces between atoms or molecules other than electrostatic (ionic), covalent (sharing of electrons), or hydrogen bonding (sharing a proton); generally ascribed to dipolar and dispersion effects, π-electrons, and the like; these relatively nondescript forces contribute to the mutual attraction of organic molecules.

van der Waals forc·es

(vahn der valz fōrs'ĕz)
Attractions first postulated by J.D. van der Waals in 1873 to explain deviations from ideal gas behavior seen in real gases; the attractive forces between atoms or molecules other than electrostatic (ionic), covalent (sharing of electrons), or hydrogen bonding (sharing a proton); generally ascribed to dipolar and dispersion effects, π-electrons, and other factors; these relatively nondescript forces contribute to the mutual attraction of organic molecules.

van der Waals forces

Weak attractions between non-polar parts of molecules. (Johannes D. van der Waals, Dutch physicist and Nobel laureate, 1837–1923).

van der Waals,

Johannes D., Dutch physicist and Nobel laureate, 1837-1923.
van der Waals forces - explains deviations from ideal gas behavior seen in real gases. Synonym(s): London forces
References in periodicals archive ?
Caption: Figure 10: Intermolecular forces for moisture attraction on vegetable oil droplet surfaces.
In the third category, intermolecular forces could be at least partially responsible for mediating a bodily response by contributing to the stereochemistry of a binding interaction.
Signal-response analyses of the limiting cases of a non-slipping film on an inclined plane (b [right arrow] 0) and of plane viscous liquid sheets (b [right arrow] [infinity]), both in absence of intermolecular forces ([PHI] = 0), have been investigated by Alleborn and Raszillier (2004a,b) and Raszillier (2005), repectively, where also details of the derivation of velocity, pressure and interface perturbations are given.
So our task would have to be that of relating the experimental stress to whatever we can discover as a rational average of the intermolecular forces in a solid.
5-Bromonicotinic acid is a relatively simple molecule that can, in principle, provide important information about competition between intermolecular forces since it has limited conformational flexibility and there are relatively few primary supramolecular assemblies that can be envisaged (Scheme 3).
Tomasi, Electronic Molecular Structure, Reactivity and Intermolecular Forces: An Euristic Interpretation by Means of Electrostatic Molecular Potentials, Adv.
Plasticizers serve as polymer additives to decrease the intermolecular forces between the polymer chains.
The individual chains are not covalently bonded to each other, but instead rely on intermolecular forces, such as Van der Waals forces, hydrogen bonding, and dipole interactions, to keep the chains from disentangling.
The substitution of polar hydroxyl groups with less polar acrylate groups led to a decreased viscosity, that can be explained by the reduction of intermolecular forces. IR spectroscopy was used to identify the characteristic vibration signals of OFI groups and double bonds, with the first showing decreased intensity and the latter appearing with acrylation.
She provides an overview of pharmaceutics, covering dosage form design; intermolecular forces and the physical and pharmaceutical properties of drugs; dispersed systems; the properties of solutions and manipulation of solubility; chemical stability; drug travel from dosage form to receptor; bioavailability, bioequivalence, and the Biopharmaceutical Classification System; parenteral drug delivery; delivery of biopharmaceuticals and the use of novel carrier systems; oral delivery of immediate release dosage forms and modified release solid dosage forms; and drug delivery by various routes of administration.
The three concepts chosen were Le Chatelier's Principle (and dynamic chemical equilibria more broadly), Intermolecular Forces (and other interparticle forces) and Thermochemistry.
The difference of morphologies can be mainly attributed to the different strengths of the intermolecular forces, such as hydrophobic force between alkyl methylene chains and [pi]-[pi] stacking of azobenzene segments, which can regulate the orderly staking and formation of organized aggregates in gel formation.

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