Predicting the second contribution to van der Waals interactions: A colloidal model system approach using optical laser tweezers
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초록
내용
We developed a colloidal model system to conduct the first experimental measurement of the dipole-induced dipole (D-I) interaction. The D-I interaction, called the Debye interaction, is the second contribution of the molecular van der Waals attraction. The model system for the colloidal Debye interaction was obtained from a permanent dipole on an interface-attached particle and its induced dipole on a water-immersed particle caused by diffuse layer polarization. We found that the scaling behavior of the D-I interaction directly measured by optical laser tweezers showed good agreement with the theoretical prediction in molecular space. The dipole character propagates along the dipole-induced electric field, leading to the formation of colloidal aggregate chains. The D-I interaction initiated the attraction in relatively long-range separation, and the van der Waals attraction became dominant for relatively short-range separations.