Synthesis of an amphiphilic spiro‐multiblock copolymer via thiol‐ene click chemistry

Abstract

A multiblock [poly(ethylene oxide)‐b‐spiro‐polystyrene] ([(PEO‐b‐spiro‐PS)]) copolymer with a topologically novel architecture was synthesized using thiol‐ene step‐growth polymerization reaction. Spiro‐PS with dimercapto groups as the hard segment was synthesized in three main steps: (a) preparation of tetra‐arm PS by atom transfer radical polymerization and the conversion of the chain‐end group to azide functionality, (b) alkyne‐azide click coupling reaction to synthesize a tricyclic PS, and (c) tactical ring opening of the tricyclic PS through disulfide/thiol redox reaction. The PEO soft segment was obtained as chain‐ends modified with norbornene groups. Finally, the hydrothiolation of the highly reactive norbornene chain‐ends of polyethylene glycol with the dimercapto groups of spiro‐PS produced the multiblock ([(PEO‐b‐spiro‐PS)]) copolymer in quantitative yield. The multiblock copolymer was characterized using size‐exclusion chromatography, proton nuclear magnetic resonance spectroscopy, Fourier‐transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and Raman spectroscopy. © 2019 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 132–138

Microphase Separation of Statistical Multiblock Copolymers

“…Multiblock copolymers have been actively studied in the last decade, particularly because of the newly developed synthetic methods. − Similar to diblock and triblock copolymers, multiblock copolymers are capable of self-assembly into micelles in solution and into bulk microstructures in melts. Materials from multiblock copolymers demonstrate a number of advantageous properties, such as enhanced mechanical stability and ion conductivity, improved control of drug release from micelles, suitable nanoparticles for bioimaging, and even antimicrobial properties. − ,− …”