[Determination of surface energy of PS-PEO-PS triblock copolymers by inverse gas chromatography].

The surface energy(gamma sd) of the dispersive component of the triblock copolymers, poly(styrene)-poly (ethylene oxide)-poly(styrene)(PS-PEO-PS), was determined by using inverse gas chromatography(IGC). A series of linear alkanes were used to determine the free energy of adsorption (delta GCH2) of a CH2 group in a temperature range of 70 degrees C-120 degrees C, and gamma sd of PS-PEO-PS were calculated. The effects of the polymer composition and temperature on gamma sd values were discussed. IGC data indicated that gamma sd values of PS-PEO-PS were lower (gamma dPS-PEO-PS-1 = 16.99 mJ.m-2, gamma dPS-PEO-PS-2 = 17.98 mJ.m-2, 70 degrees C) than that of PEG (gamma dPEG = 21.74 mJ.m-2, 70 degrees C), and increased as the ethylene oxide content increased in PS-PEO-PS. The gamma sd was sensitive to temperature, decreased sharply with the increase of temperature. Linear relationships were obtained between the gamma sd and temperature (t, degree C), which were gamma dPE-PEO-PS-1 = 28.12-0.161t and gamma dPS-PEO-PS-2 = 28.23-0.148t.