Five diblock copolymers consisting of polybutadiene spheres in a polystyrene matrix were synthesized and characterized using several techniques, including transmission electron microscopy and small-angle neutron scattering (SANS). The mean radius of the polybutadiene spheres as measured from the electron micrographs was found to be significantly smaller than the SANS value for each of the samples (the average value of REM RSANS was 0.77). This discrepancy is greater than can be accounted for by sphere truncation when sectioning the sample for the electron microscope and is believed to be an artifact of the staining procedure.
Bibliographical noteFunding Information:
This research was supported by the National Science Foundation, Division of Materials Research-Polymers Program under grant DMR-8001674 with additional help from DMR-7824185. SANS experiments were performed at the National Center for Small-Angle Scattering Research (NCSASR) which is funded by NSF grant DMR-7724458 through interagency agreement 40637-77 with DOE. The Center is operated by Union Carbide Corporation under DOE contract W-7405-eng-26. The assistance of Dr George Wignall of NCSASR is gratefully acknowledged, and we thank Dr George Hadziioannou of the University of Massachusetts, Amherst, for obtaining the SAXS data. We have also benefitted from the availability of plotting routines developed by Chris Schwier and Martin Suenson, and from stimulating conversations with Dale Handlin and Professor E. L. Thomas of the University of Masschusetts, Amherst.
- diblock copolymers
- electron microscopy
- small-angle scattering
- sphere sizes