LIGHT-SCATTERING OF SPINNABLE, VISCOELASTIC SOLUTIONS OF HEXADECYLTRIMETHYLAMMONIUM SALICYLATE

Static, dynamic, and electrophorelic light scattering were measured for spinnable, viscoelastic solutions of hexadecyltrimethylammonium salicylate with and without sodium salicylate (NaSal) at various temperatures. While short rodlike micelles are formed in aqueous solutions without NaSal, the length of rodlike micelles increases with an increase in NaSal concentration and reaches 2000-3000 nm in 0.1 M NaSal. However, the size diminishes above 0.5 M NaSal, and small micelles exist in 1 M NaSal. The external interference effect indicating a strong intermicellar correlation is quite apparent in aqueous solutions without NaSal, but it decreases with addition of NaSal and is imperceptible above 0.001 M NaSal. The electrophoretic mobility changes sign from positive to negative with addition of 0.1 M NaSal, indicating the reversal of the net micelle charge. The pseudolinkages between short rodlike micelles, in which salicylate ions participate, would be constructed in aqueous solutions without or with a small amount of NaSal, and the entanglement of long rodlike micelles exists, besides the pseudolinkages, in aqueous solutions with a medium amount of NaSal. © 1990 American Chemical Society.