Calculated using classical electromagnetism, the van der Waals force increases without limit as two surfaces approach. In reality, the force saturates because the electrons cannot respond to fields of very short wavelength: polarization charges are always smeared out to some degree and in consequence the response is nonlocal. Nonlocality also plays an important role in the optical spectrum and ...

An investigation is presented of the interaction of charged self-assembled monolayers (SAMs) with a monoprotic ionizable acid functional group (-COOH) and uncharged SAMs with a methyl terminated functional group (-CH(3)). The strength of the interactions are determined using an atomic force microscope. For all electrolyte conditions investigated the interactions are not well described by a summ...

It was recently suggested that the swelling of neutral multilipid bilayers upon addition of a salt can be simply explained only by the electrolyte screening of the van der Waals attractions, while assuming that the hydration force and the repulsion due to thermal undulations of membranes are unaffected by the salt. While we agree that the screening of the van der Waals interactions plays a role...

Cellular structures are shaped by hydrogen and ionic bonds, plus van der Waals and hydrophobic forces. In cells crowded with macromolecules, a little-known and distinct force-the "depletion attraction"-also acts. We review evidence that this force assists in the assembly of a wide range of cellular structures, ranging from the cytoskeleton to chromatin loops and whole chromosomes.

2 Different Types of Bonds 7 2.1 Covalent Bonding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2 Ionic Bonding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.2.1 Madelung Sums . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.3 Metallic Bonding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.4 Van der Waals Bonds . . . . . . . . . . . ....

We report high resolution simultaneous measurements of electrical conductance and force gradient between two sharp gold tips as their separation is varied from the tunneling distance to atomic-size contact. The use of atomically sharp tips minimizes van der Waals interaction, making it possible to identify the short-range metallic adhesion contribution to the total force.

where a is the plate separation; in principle, a QED effect can directly influence a macroscopic, classical, apparatus. In spite of the extensive theoretical attention this effect has received over the years (see [2,3] for recent reviews), there has been only one attempt at its measurement. This measurement, as reported by Sparnaay in 1958, showed an attractive force “not inconsistent with” the...

We study the dependence of the heat transfer and the van der Waals friction between two semi-infinite solids on the dielectric properties of the bodies. We show that the heat transfer and van der Waals friction at short separation between the solids may increase by many orders of magnitude when the surfaces are covered by adsorbates, or can support low-frequency surface plasmons. In this case t...

The van der Waals equation of state for imperfect gases is applied to solutions of macromolecules, especially to explain the fluid-fluid phase transition in protein solutions, a phenomenon of much interest in relation to protein crystallization. The van der Waals b parameter corresponds to the total excluded volume per pair of molecules and can be calculated from independently known molecular p...