Vander-Waals interactions

Aromatic polyimide(PI)s have found widespread use in microelectronics, optoelectronics, gas separation and aerospaee applieations because of their excellent electrical properties, chemieal resistanee, high meehanieal strength, high modulus and thermoxidative stability. Most aromatie Pis are intraetable due to the poor solubility in organic solvents and the insolubility is attributed to the extremely strong interchain interactions of imide rings [1] or donor-acceptor interaetions [2] in eombination with non-specific Vander Waals interactions. They are usually proeessed in their soluble precursor form namely polyamic acid (PAA), its... 

Non-bonded potentials. These typically take the form of a Coulomb potential between non-bonded pairs of atoms to describe polarisation and permanent electrostatics, and a Lennard-Jones (LJ) potential between non-bonded atom pairs to describe the vander Waals (vdW) interactions. 

VanDer Waals— London attraction forces 8. The interaction of colloidal particles.. . . ... 

For example, little is known about acid-base interactions at solid/solid interfaces. It has long been recognized that molecular interactions across the interface between condensed phases may be split into physical and chemical terms. Physical interactions (vander Waals forces) contribute to the non-ideality of fluids and have been traditionally considered for interfaces. However, modern theories explain interfacial phenomena on solid surfaces, such as adhesion or wetting, in terms of chemical interactions. Moreover, the Lewis definition of acidity is so comprehensive that it can easily be accepted that most chemical interactions at solid surfaces may be effectively described as acid-base interactions [15]. continuously growing literature reinterprets interactions at solid/solid interfaces in terms of acid-base properties. For example, their role was shown in relation to solid/solid adhesion in film-substrate or fber-matrix systems as well as in wood and paper processing,... 

Perhaps the most successful method for chiral chromatography has been to use a chiral stationary phase. This approach is based on the basic premise that there would be a three-point interaction between the stationary phase and the stereoisomers. Due to the different spatial arrangement of the functional groups at the chiral center of the enantiomers, different transient complexes of stationary chiral phase with the enantiomers will form. They will eventually allow racemic mixture to be resolved. These transient complexes may ususdly be formed by hydrogen bonding and vander waals forces. One form of the stationary phases used here is proteins (bovine serum albumin) since proteins themselves are optically active. 

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