The interaction of four poly(ethylene oxides), with molar masses of 1500, 3350, 10 000 and 100 000 g mol(-1) with sodium dodecylsulfate, at 15, 25, 35 and 65 degreesC was investigated by isothermal titration calorimetry. No significant change of the critical aggregation concentration values or of the amount of surfactant bound was observed within this temperature range. The profiles for the variation of the observed enthalpies with surfactant concentration, however, are quite different for the four studied temperatures, what has been interpreted as a consequence of a change in the mode of poly(ethylene oxide) (PEO) interaction with sodium dodecylsulfate (SDS) micelles within this temperature range. (C) 2004 Elsevier B.V. All rights reserved.