Scattering studies of poly(urea-urethane) microcapsules in suspension

Poly(urea-urethane) microcapsules containing tris(2-chloroethyl) phosphate as the core material were characterized by means of laser light scattering and synchrotron small angle X-ray scattering. The z-average hydrodynamic radius R(h) of the microcapsule was determined to be 165 +/- 7 nm from dynamic light scattering (DLS). The z-average radius of gyration R(g) = 130 +/- 4 nm from static light scattering and 120 +/- 8 nm from ultrasmall angle X-ray scattering, which coincide with the calculated value of 129 nm by using a solid sphere assumption and the value of R(h) from DLS. These results were compared with previously published data for microcapsules with the same membrane but different core materials. (C) 1996 Academic Press, Inc.