Synthesis and Micellar Properties of Star-Shaped Poly(ε-Caprolactone)-Dextran Amphiphilic Block Copolymer
6-arm star-shaped Poly (ε-caprolactone)-dextran (sPCL-dextran) was synthesized and characterized. The core of the star polymer is dipentaerythritol, the inner block in the arm is hydrophobic poly (ε-caprolactone) (PCL), and the outer block in the arm is hydrophilic dextran. The synthesis involves three steps: (1) The ring-opening polymerization of ε-caprolactone (CL) initiated by dipentaerythritol produces 6-arm star-shaped PCL (sPCL-OH). (2) The sPCL-OH reacts with acryloyl chloride to get star-shaped PCL with acrylate end group (sPCL-CH=CH2). (3) The amino ended dextran (dextran-NH2) is then attached to sPCL-CH=CH2 terminus by Micheal addition to form star-shaped sPCL-dextran. The architecture of products was characterized with 1H NMR, GPC and element analysis. Micellization of sPCL-dextran in aqueous solutions was investigated by DLS. The results showed that the micelle size (Rh) and size distribution are related to the concentration of the sPCL-dextran. Salt, pH value and temperature have no obvious influence on the Rh.
Zhong Cao, Xueqiang Cao, Lixian Sun, Yinghe He
X. Q. Liu and J. Y. Liu, "Synthesis and Micellar Properties of Star-Shaped Poly(ε-Caprolactone)-Dextran Amphiphilic Block Copolymer", Advanced Materials Research, Vols. 239-242, pp. 2711-2716, 2011