Interfacial binding force

A more vital application is to discern how reinforcement surface treatments improve adhesion to thermoplastic matrices. Since the nonreactive nature of thermoplastics normally precludes interfacial covalent bond formation, secondary bonding forces, such as London dispersion interactions and Lewis add/base interactions, may play a major role in these drcumstances. These secondary binding forces are subject to surface energetics analysis. 

In studies of films of fatty acids it was found that a pH exists where various interfacial properties show a distinct peak [17], This optimum was near the p a of the fatty acid salts as determined by titration with NaOH. The increase in p a for saturated fatty acids with increasing chain length was explained by the possibility of closer packing and stronger binding forces of longer fatty acid chains. Unsaturated fatty acids had lower p/fa... 

The surface properties of this kind of supramolecular systems are really scarce. An interplay between short - range van der Waals forces, ionic binding, chemical bonding, elastic/plastic compression, and long - range electrostatic interactions and capillary forces between macromolecules and surfaces seems to be responsible for the variety of observed interfacial behaviors. 

Mobile liquid binding produces cohesion through interfacial forces and capillary suction. Three states can be distinguished in an assembly of particles held together by a mobile liquid (Fig. 21-92). 

Smectite clays consist of 1 nm thick aluminosilicate layers separated by sodium and calcium counterions. As little as 1 to 5 wt% of these layered clays can significantly improve the mechanical properties of nylon, polyolefins, and other polymers (78). Delaminating the clay structure by replacement of the sodium or calcium ions with a polymer-compatible surfactant, a quaternary ammonium ion surfactant, for example, is essential to generate a large polymer-clay interfacial area, as shown in Figure 11.21 (79). Ammonium ion head groups of the dispersant bind to the surface of the clay by Coulombic forces, and the hydrophobic alkyl tails bind to the polymer by van der Waals forces. 

Interestingly, double-layer electrostatic forces induced inclusion of inorganic cations and anions into CyD monolayers leading to an increase in the interfacial capacitance. Anion binding constants were obtained from the dependence of capacitance current on anion concentration. The charge density in the plane of nitrate inclusion is a function of total surface concentration of CyD and the nitrate occupancy. The electrostatic contribution to the potential was determined and used for the calculation of corrected binding constant for nitrates (0.11 M for f -... 

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