writer：WEIZHONG YUAN, JINYING YUAN, MI ZHOU, CAIYUAN PAN
keywords：atom transfer radical polymerization (ATRP), dendrimers, fluorescence, ring-opening polymerization, star-shaped dendrimer-like copolymer
source：期刊
Issue time：2008年

Novel and well-defined pyrene-containing eight-arm star-shaped dendrimer-
like copolymers were successfully achieved by combination of esterification,
atom transfer radical polymerization (ATRP), divergent reaction, ring-opening polymerization (ROP), and coupling reaction on the basis of pentaerythritol. The reaction of pentaerythritol with 2-bromopropionyl bromide permitted ATRP of styrene (St) to form four-arm star-shaped polymer (PSt-Br)4. The molecular weights of these polymers could be adjusted by the variation of monomer conversion. Eight-hydroxyl starshaped polymer (PSt-(OH)2)4 was produced by the divergent reaction of (PSt-Br)4 with diethanolamine. (PSt-(OH)2)4 was used as the initiator for ROP of e-caprolactone (CL) to produce eight-arm star-shaped dendrimer-like copolymer (PSt-b-(PCL)2)4. The molecular weights of (PSt-b-(PCL)2)4 increased linearly with the increase of monomer. After the coupling reaction of hydroxyl-terminated (PSt-b-(PCL)2)4 with 1-pyrenebutyric acid, pyrene-containing eight-arm star-shaped dendrimer-like copolymer (PSt-b-(PCL-pyrene)2)4 was obtained. The eight-arm star-shaped dendrimer-like copolymers presented unique thermal properties and crystalline morphologies, which were different from those of linear poly(e-caprolactone) (PCL). Fluorescence analysis indicated that (PSt-b-(PCL-pyrene)2)4 presented slightly stronger fluorescence intensity than 1-pyrenebutyric acid when the pyrene concentration of them was the same. The obtained pyrene-containing eight-arm star-shaped dendrimer-like copolymer has potential applications in biological fluorescent probe, photodynamic therapy, and optoelectronic devices.