The recent studies deal with a diblock copolymer, polystyrene poly(ethylene oxide). Infrared spectroscopy, proton resonance spectroscopy (H-1-NMR), and laser light scattering techniques have been used to characterize the polymer. It has been concluded that the sample investigated is diblock copolymer polystyrene poly(ethylene oxide) having molecular mass 1.656 x 10(4) g/mol and blocks ratio 1 : 2. The micellization behavior is explored through H-1-NMR, laser light scattering, light absorption, surface tension, and conductance and viscosity measurements. The results conclude that the critical micelles concentration of copolymer is 0.0951 g/dL at 25 degrees C. It has been observed that the surface tension of solution decreases with the temperature and its impact is maxima in dilute concentration region. In addition, new methodologies have been introduced to get accurate critical micelles concentration and critical micelles temperature. (C) 2010 Wiley Periodicals, Inc., J Appl Polym Sci 118: 1704-1712, 2010