Jj. Leahy et al., The effects of radiofrequency electromagnetic radiation on the adhesion behavior of aqueous suspensions, J COLL I SC, 225(1), 2000, pp. 209-213
The effect of radiofrequency treatment on the adhesion behavior of amidine
and carboxylated polystyrene latexes was investigated. The isoelectric poin
ts pH(IEP) of copper and zinc were initially measured as 9.4 and 9.5, respe
ctively, using a technique proposed by N. Kallay, Z. Torbic, M. Golic, and
E. Matijevic [J. Phys. Chem. 95, 7028 (1991)] based on the attachment of ch
arged colloids to metallic surfaces in an aqueous medium. Statistical analy
sis showed that the technique was repeatable with a coefficient of variatio
n less than 6% and an accuracy greater than 95%. The effect of a radiofrequ
ency signal (27 MHz) on adhesion behavior was evaluated and it was found th
at there was reduced attachment at pH values when the colloid and metallic
surface were oppositely charged and enhanced attachment between similarly c
harged particles. It is proposed that this is due to a reduction in the sur
face potential of the charged particles due to thickening of the adsorbed l
ayer by hydrogen and hydroxyl ions. (C) 2000 Academic Press.