Formation and hosting properties of polyacrylate-surfactant complexes

The different complexation between surfactants and polymers can influence the hosting properties of the formed system. If the polymer is hydrophobically modified, the behavior is even more exciting. Therefore, we study the surfactants impact on hydrophobically modified sodium polyacrylates (NaPAC (n) , n = 10 and 18), polyacrylic acid (PAA), and sodium polyacrylate (NaPA) being also considered for comparison. Ethoxylated, anionic, and cationic surfactants with the same hydrophobic chain length (i.e., C-12) are employed. Generally, the occurrence of critical aggregation concentration depends on the interplay of hydrophobic and electrostatic forces between species. For example, the nonionic surfactant interacts most strongly with PAA (by hydrogen bonds), the anionic one with NaPAC(18) (by weak hydrophobic forces), and the cationic surfactant with NaPA (by strong electrostatic interactions). The hosting ability of the systems is tested using pyrene and 3-methoxy-7H-benzo[de]anthracen-7-one (MBA) as fluorescent guests. The fluorescence data reveal that the probes solubilize in the micellar palisade layer, their lifetime and/or intensity being higher in these protected media. Moreover, it is exposed that the less hydrophobic MBA interacts with the surfactants and polymers as well. This leads to dye-chemical species complexes with short fluorescence lifetimes. All the present chemical species interact with dodecanol impurity.