Cryo-TEM of Polyelectrolyte-Micelle Complexes

Cryo-TEM was carried out on samples containing polyelectrolyte-micelle complexes, formed by combining poly(diallyldimethylammonium chloride) (PDADMAC), a strong cationic polyelectrolye, with oppositely charged mixed micelles of sodium dodecyl sulfate (SDS) and nonionic Triton X-100 (TX100), in 0.40 M NaCl. Complexation appears to involve the formation of micelle-rich regions, presumably within the domains of polymer chains, without any particular organization or restructuring of the micelles. At polymer concentrations (CP) </= 0.4 g/L, the observation of such clusters with dimensions as low as 50 nm suggests that intrapolymer complexes may exist at low CP. With increasing polymer concentration, aggregates grow in size, with dimensions that indicate the involvement of many polymer chains. Upon increase in the ratio of SDS:TX100, the system coacervates, and the micelle/polymer-rich phase forms a continuous matrix.