Two rapidly convergent series for calculating the interaction energies between two dissimilar double layers for Na2SO4 or CaCl2 types asymmetric electrolytes at y0 > 0 > yd ≥ −y0

• Published in: Colloid journal of the Russian Academy of Sciences 2009, Vol.71 (5)
• Main Authors: Zhang, Shimin, Jiang, Jianghong
• Format: Article
• Language: English
• Subjects: Chemistry; Chemistry and Materials Science; Polymer Sciences; Surfaces and Interfaces; Thin Films
• ISSN: 1061-933X; 1608-3067
• DOI: 10.1134/S1061933X09050056

Two rapidly convergent series for calculating the interaction energies between two dissimilar double layers for Na 2 SO 4 or CaCl 2 types asymmetric electrolytes at y 0 > 0 > yd ≥ − y 0 were derived, the number of the series terms required to obtain the interaction energies with six significant digits is not more than 4 when the dimensionless surface potential of two dissimilar double layers changes from −20 to + 20. The absolute values of the interaction energies V between two dissimilar double layers for Na 2 SO 4 , CaCl 2 and NaCl types electrolytes obey the following relations: when − y d = y 0 , V ′Na 2 SO 4 = V ′CaCl 2 ; when − y d > y 0 , V ′Na 2 SO 4 > V ′CaCl 2 ; when − y d < y 0 , V ′Na 2 SO 4 < V ′CaCl 2 ; V ′Na 2 SO 4 or V ′CaCl 2 is always less than V ′ NaCl . Several approximate expressions were given for interaction energy at y 0 and − y d ≪ 1.