Obviously, cantilever C4 is acted by two forces: one is the van der Waals force
at the CNT/Au contact interface, and the other is the elastic resilience force resulting from elastic deformation.
Coaxial DWCNTs are modeled as two beams interacting between then through van der Waals forces
, and nonlocal Euler-Bernoulli beam theory is employed in order to calculate the free vibration frequencies of the system.
Taking a derivative of U (r) relative to r, an expression for the van der Waals force
Although ionic forces make the major contribution to the total energy, after a separation of 6-8 [Angstrom], the van der Waals forces
dominate and are most effective at large separations.
If a change in the relative retention time as a result of cyclization is caused by a change in the size of the molecule moving in a chromatographic column and a change in both intramolecular and intermolecular van der Waals forces
, then the related cyclization of alkyl chain could really be, in the case of n-alkylphenols, accompanied by formation of a hydrogen bridge between the oxygen in the phenolic group -OH and a hydrogen of the terminal group -C[H.sub.3] of the alkyl; in other words, in the case of n-alkylphenols, the tendency to form hydrogen bridges resulting in a heterocyclic ring with six or more members being formed including also one C-C bond of the aromatic ring of phenol as shown in Fig.
The fitting of the experimental force data was done using a theoretical model combining both electrostatic and van der Waals forces
for a conical tip-flat substrate system, and this fitting allowed the determination of the surface charge density of the bitumen-water interface.
An interdisciplinary team of researchers, led by Autumn, later confirmed speculation that the gecko's climbing ability depends on van der Waals forces
, which are weak electrodynamic forces that operate over very small distances but bond to nearly any material.
In the 16 October 2003 Advanced Materials article, Lee explains: "In the natural state, [montmorillonite] platelets are held together by van der Waals forces
and electrostatic forces to form crystallites (tactoids).
Typically, foam-causing components stabilize foam because of ionic forces, hydrogen bonding, and van der Waals forces
. In aqueous systems, molecular defoamers destabilize the foam by disrupting these forces and causing the foam to collapse--thereby reducing surface defects.
It is believed that this enhanced polyurethane-particle adhesion is a result of greater van der Waals forces
, more similar solubility parameters and even covalent bond formation.
The crystal structure of |MoO.sub.3~, for example, is comprised of Mo-O octahedra connected to form a 2D-sheet lattice 7 |Angstrom~ thick, in which the sheets are bonded together by Van der Waals forces
. Mo|O.sub.3~ is a oxidation catalyst; it is also a promising material for many solid state ionic applications, including electrochromic devices and reversible batteries.
Due to the strong intermolecular van der Waals forces
existing among graphene nanosheets, achieving homogenous and well exfoliated graphene sheets with single or few layers in both solvents and polymers is challenging.