The thermosensitive polyelectrolytes were obtained by grafting 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) onto hydroxypropylcellulose (HPC), a biodegradable polysaccharide. The interactions of the polymers with dodecyltrimethylammonium chloride (DTAC), a model cationic surfactant, were studied. It was found by the measurements of the surface tension and the analysis of fluorescence emission of pyrene used as a fluorescent probe, that the HPC-AMPS graft polymers strongly interact with DTAC with the formation of polymer-surfactant complexes. The critical aggregation concentrations of these polymer-surfactant systems were found to be of the order of 10(-5) mol/dm(3). The polymers were found to be potentially useful in the purification of water from cationic surfactants. (c) 2006 Wiley Periodicals, Inc.