SMALL PBS CLUSTERS PREPARED VIA ROMP BLOCK COPOLYMER TECHNOLOGY

Small particles of lead sulfide have been prepared by H2S treatment of block copolymer films wherein aggregates of poly[(C7H9CH2C5H4)2Pb] reside as microdomains distributed throughout a polynorbornene matrix. The block copolymers were prepared by sequential addition of 200 equiv of norbornene and 5, 10, and 20 equiv of (C7H9CH2C5H4)2Pb (1) to Mo(CH-t-Bu)(NAr)(O-t-Bu)2 (Ar = 2,6-C6H3-i-Pr2), followed by quenching with benzaldehyde. The interdomain spacings (320-480 Å) before and after H2S treatment were revealed by small-angle X-ray scattering (SAXS). Average cluster diameters (20-40 Å) were determined by transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). The clusters were identified as PbS by X-ray fluorescence analysis performed on the STEM and by wide-angle X-ray powder diffraction. © 1990, American Chemical Society. All rights reserved.