Extraction of naphthalene by block copolymer surfactants immobilized in polymeric hydrogels

Gel/micelle materials, comprising hydrogels containing block copolymer micelles, have the potential to be very useful in a variety of extraction and controlled release applications. It is demonstrated that block copolymer surfactants can be immobilized in calcium alginate gels and that the resulting composite material preferentially solubilizes the model hydrophobic solute naphthalene. Five different polyethylene oxide‐polyropylene oxide‐polyethylene oxide triblock copolymer surfactants are considered, and the qualitatively different properties exhibited are interpreted in light of the properties of these surfactants in solution. Alginate gel concentrations of 22.5 and 52.5 g/L and surfactant concentrations ranging from 20.4 to 136 g/L are considered. The data indicate that micelles can be permanently immobilized for purposes of extraction or controlled release and that the extent of solute uptake or release can be altered by varying gel and surfactant concentration and the type of surfactant employed.