Charge leakage

Charge- leakage breakdown of the classical ionic picture lithium fluoride... 

In LiF (,1 1) ion-dipole complexes, donor-acceptor charge leakage from F to Li+ is apparent in each member of the series, but the incremental CT, expressed as a percentage of a full electronic charge, is progressively weakened with each added F ion,... 

An irradiation-induced expansion could conceivably be caused by the ions, formed as precursors of the radicals, or by thermalized electrons trapped within the polymer. Irradiation induces electrical conductivity in polymers, and this conductivity decays after irradiation is ceased (4, 5). The decay process is accelerated by increased temperature or plasticity of the specimen, presumably by facilitating leakage of the trapped electrons or ions to ground. One might speculate that the sample expands upon irradiation because of the local mutual electrical repulsions of like charges which are trapped in the polymer matrix, and that both increased temperature and plasticizer content diminish this expansion because of charge leakage out of the specimen. It is difficult to prove or disprove this hypothesis. 

The sample with Raven 5750 carbon black shows a decrease in charge at 400V from linear behavior although not as large a drop as with the Regal 330 or Vulcan samples. The Raven 5750 sample has a constant resistivity of 2.3 x 10 n cm, somewhat lower than the resistivity for a true insulator. The charge leakage phenomenon may be present for this sample. 

Takahashi, H., K. Sato, S. Sakata, and T. Okada, Charge Leakage Characteristic of Glass Substrate for Liquid Crystal Display, J. Electrostatics, 35, 1995, pp. 309-322. 

Change in Coulomb Forces upon Charge Leakage. The charge on particles covering a grounded surface is not constant. This charge falls off as the time... 

Considering that the surfaces of dielectric particles carry adsorbed layers that impart surface conductance to the particles, i.e.,R i=- o, we can expect that charge leakage will always take place to some degree or another. Then the magnitude of the image force will decrease as the time spent by the adherent particle on the grounded surface is extended. 

The separation of dusts into classes is somewhat arbitrary since the contact potential difference and the rate of charge leakage will depend not only on the dust properties, but also on the properties of the paint or varnish coating. 

Thus we see that in order to ensure maximum adhesion of Class I dust (i.e., nonaggregating dust) and prolonged action of the charged substrate, the contact potential difference between the surface of the particles must be maximized, and the rate of charge leakage upon contact must be minimized. 

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