Discussion on the position of the shear plane

The study of zeta potential is very important in the field of colloid and interface chemistry. The zeta potential is the potential at the shear plane. However, at present, people do not know the actual position of the zeta potential or the shear plane in the diffuse double layer of a colloid. The general opinion is that the position of the zeta potential in the diffuse double layer is very close to the Stem plane. In this paper, according to the Gouy-Chapman theory and the related published experimental results, a new opinion, that the position of zeta potential in the diffuse double layer is close to the Gouy plane, has been suggested. Based on the new point of view, the Gouy-Chapman theory was used in the prediction of swelling pressure of clay minerals, and it was found that the theoretical curve agrees with the experimental data very well. (C) 2003 Elsevier Science (USA). All rights reserved.