A SAXS STUDY OF THE INTERNAL STRUCTURE OF DENDRITIC POLYMER SYSTEMS

Small-angle x-ray scattering was used to characterize the single-parti cle scattering factors produced by poly(amidoamine) dendrimers, poly(p ropleneimine) dendrimers, and polyol hyperbranched polymers in dilute solutions with methanol as solvent. Fits from electron density modelin g reveal similar overall densities of the dendrimers as a function of dendrimer generation. The seventh through tenth generation poly(amidoa mine) dendrimers exhibit higher order scattering features that require nearly monodisperse, spherical particles with essentially uniform int ernal segment densities. Dilute hyperbranched polymer solutions exhibi t scattering more indicative of the inherent irregularity of internal segment densities and overall sizes to be expected within these system s. Radii of gyration estimated from electron density modeling agree re asonably well with those estimated by standard Guinier methods used in previous studies. (C) 1997 John Wiley & Sons, Inc.