Precise Synthesis of PS‐PLA Janus Star‐Like Copolymer. Issue 5 (22nd July 2018)

• Record Type: Journal Article
• Authors: Fan, Xiaoshan; Win, Khin Yin; Hu, Zhiguo; Loh, Xian Jun; Li, Zibiao
• Other Names: Loh Xian Jun guestEditor.; Li Zibiao guestEditor.
• Is Part Of: Macromolecular rapid communications. Volume 40:Issue 5(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-07-22
• Subjects: asymmetric structures -- Janus copolymers -- precise synthesis -- star‐shaped polymers; Macromolecules -- Periodicals; Polymers -- Periodicals; Chemistry -- Periodicals; 547.705
• DOI: 10.1002/marc.201800217
• Languages: English
• ISSNs: 1022-1336

Abstract

Abstract: In this work, an efficient strategy is designed for the precise synthesis of novel Janus star‐like copolymer (polystyrene)8 ‐ b ‐(poly(l ‐lactide))8, (PLLA)8 ‐ b ‐(PS)8, consisting of two types of chemically distinct polymer arms, PS and PLLA, in an asymmetric structure. During the synthesis, PLLA hemisphere carrying protected hydroxyl groups at the focal point was first synthesized via a combined reactions of esterification, light‐induced "Click" chemistry, and ring opening polymerization (ROP) using a specially designed dendron as initiator. After removing the protecting moiety, the terminal hydroxyl groups on the dendron segment is increased fourfold and further modified into bromopropionate‐based macroinitiator through a two‐step end group transformation reaction, followed by atom transfer radical polymerization (ATRP) of styrene to obtain the desired (PLLA)8 ‐ b‐ (PS)8 Janus star‐like copolymer. The versatility and efficiency of the designed synthetic strategy are demonstrated by the well‐defined molecular characteristics and high yields of the targeted product. In addition to the controlled degradation behavior of the PLLA segments, the remaining bromide groups located at the distal end of PS arms could allow for further fabrication of diverse building blocks through consecutive ATRP of various monomers. This work signifies the first time for facile and precise synthesis of Janus star‐like copolymer with unique biphasic structure and function control. Abstract : A new strategy for the precise synthesis of Janus star‐like copolymer (polystyrene)8 ‐ b‐ (poly(l ‐lactide))8 (PLLA)8 ‐ b ‐(PS)8 is developed through a multifunctional dendron design, combined with esterification, light‐induced "Click" chemistry, ring opening polymerization (ROP), and atom transfer radical polymerization (ATRP). The versatile synthetic platform presented in this study provides a new opportunity for the successful synthesis of an asymmetric copolymer with precise structure and functional control.