Small lead sulfide (PbS) clusters prepared via ROMP block copolymer technology

Abstract

Small particles of lead sulfide have been prepared by H{sub 2}S treatment of block copolymer films wherein aggregates of poly((C{sub 7}H{sub 9}CH{sub 2}C{sub 5}H{sub 4}){sub 2}Pb) 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 (C{sub 7}H{sub 9}CH{sub 2}C{sub 5}H{sub 4}){sub 2}Pb (1) to Mo(CH-t-Bu)(NAr)(O-t-Bu){sub 2} (Ar = 2,6-C{sub 6}H{sub 3}-i-Pr{sub 2}), followed by quenching with benzaldehyde. The interdomain spacings (320-480 {angstrom}) before and after H{sub 2}S treatment were revealed by small-angle x-ray scattering (SAXS). Average cluster diameters (20-40 {angstrom}) 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.