Bonding, chemical electrostatic

Depending on the level of interaction between these organic-inorganic phases, hybrid materials can either possess weak interaction between these phases such as van der Waals, hydrogen bonding, or electrostatic interaction [7,8], or be of strong, chemically bonded (covalent or coordinate) types [9]. 

U = (/chemical bonds I (/electrostatic I (/Leri nard-Jones... 

In this building-block approach, the components are synthesized separately and then hybridized via linking agents/methods that utilize covalent, noncovalent (van der Waals, n-n interactions, hydrogen bonding), or electrostatic interactions. The attachment of these building blocks often requires the chemical modification of at least one component to overcome the differences in surface chemistry. As a consequence deposition is often limited to the first layer. Excess nanoparticles can be removed by filtration or centrifugation. 

Of the more than one hundred elements that occur in nature or that have heen produced synthetically, only the nohle gases exist naturally as single, uncomhined atoms. The atoms of all other elements occur in some combined form, bonded together. Chemical bonds are electrostatic forces that hold atoms together in compounds. 

Table 6.2 SMARTS patterns for chemical features (HBA-F, hydrogen bond acceptor/electrostatic fluorine interaction HBD, hydrogen bond donor PI, positive ionizable Nl, negative ionizable)...

Figure 13. Intermolecular interactions in the y-form crystal of racemic NPMe3 viewed (a) down the c axis and (b) along the c axis, and (c) the schematic representation of the homochiral 1-D chain structure, in which the ellipsoid and circle indicate the ammonium ion and sulfonate ion, respectively. The dashed lines show the intermolecular hydrogen bonds and electrostatic interactions. (Reprinted with permission from ref 26. Copyright 2003 American Chemical Society.)...

Jones, M.R.O., and Bond, J., Electrostatic hazards associated with marine chemical tanker operations Criteria of incendivity in tank cleaning operations, Chem. Eng. Res. Des., 62, September 1984. 

Enzymes can also be entrapped in polymeric networks either by physical entrapment, chemical bonding or electrostatic attraction. Physical entrapment is very simple because it only involves dissolving the enzyme and subsequent irradiation to yield hydrophilic gels with entrapped enzymes of high reactivity and low leakage [23],... 

Therefore, as generally described by Pauling, the diatomic dications having formal single (He22+), double (NF2+) or triple (022+) bonds all seem to be well described as ordinary chemical bonds plus electrostatic repulsion<8 10). 

Adsorption could generally be classified as physical adsorption and chemical adsorption. Forces involved in adsorption include van der Waals force, hydrogen bonding or electrostatic force in physical adsorption, and covalent chemical bonds in chemical adsorption. Adsorption could occur between solid and solid, solid and liquid, or solid and gas. In pharmaceutical development, these adsorptions could take place during different processing stages, and affect the properties of the final products. There are cons and pros of these adsorptions, which will be discussed in this article. 

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