Thiol is a useful functional group due to its high affinity to heavy metal (Au, Ag, Hg, Pb). For example, thiol-terminated polymers can be used as surface modifier in gold nanoparticle (Au-NP) synthesis. In this work, thiol-terminated polystyrene (PS-SH) was prepared by anionic polymerization of styrene followed by the chain end functionalization via a reaction with propylene sulfide. As-synthesized PS-SH were characterized by size-exclusion chromatography (SEC), liquid chromatography at the critical condition (LCCC), interaction chromatography (IC) and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF MS).
The end-fuctionalization reaction was not quantitative. Homo-polystyrene and PS-SH with oligomeric propylene sulfide end group were always formed according to the MALDI-TOF MS analysis. In addition, coupled products via disulfide linkage were also observed. To understand the reaction mechanism leading to various by-products, PS-SH samples were synthesized at varying stochiometric ratios of polystyryl anions to propylene sulfide and characterized by chromatography and mass spectrometry. For
chromatographic separation of PS-SH from other side-products, IC and LCCC were more effective since
SEC separates polymers according to the size and is incapable of separating polymers according to the