SYNCHROTRON SAXS MEASUREMENTS ON SOLUTIONS OF POLY(STYRENE-ISOPRENE) AB-BLOCK COPOLYMER IN ANILINE

Synchrotron small angle X-ray scattering (SAXS) has been performed on solutions of a poly (styrene-isoprene) AB block (PS/PIP) copolymer in aniline. The copolymer forms aggregates in this particular solvent. Earlier investigations could not determine whether the aggregates were micelle-like or vesicle-like. In order to distinguish between these two possibilities, the form factor has to be known over a wide range of the scattering vector (q) to within a satisfactory precision. Due to the high intensity of synchrotron radiation, it was possible to obtain SAXS results with a sufficient precision, which allowed the conclusion that the aggregates were vesicle-like when the PS block was sufficiently short. The effect of polydispersity on the form factor is also discussed. © 1990.