Synthesis of cyclic polymers and topology effects on their diffusion and thermal properties

Abstract

In comparison with their linear counterparts, cyclic polymers exhibit distinctive properties due to their topology. The synthesis of cyclic polymers and the functionalities arising from their unique shapes, namely topology effects, are reviewed. The electrostatic self-assembly and covalent fixation (ESA-CF) process was used in conjunction with click chemistry and with olefin metathesis to construct selectively a variety of unprecedented polymer architectures, such as manacle-shaped and tandem multicycles, as well as doubly fused tricyclic and triply fused tetracyclic topologies. Moreover, the self-assembly of a cyclic amphiphilic block copolymer, which was prepared by intramolecular metathesis, produced micelles that exhibited an increase in thermal stability of approximately 50 °C compared with the micelles formed from the linear prepolymer. Single-molecule spectroscopic studies also revealed different diffusion modes for cyclic and linear polymers. The electrostatic self-assembly and covalent fixation (ESA-CF) process, in conjunction with click chemistry and olefin metathesis, was used to construct selectively a variety of unprecedented polymer architectures, such as manacle-shaped and tandem multicycles, as well as doubly fused tricyclic and triply fused tetracyclic topologies. Moreover, the self-assembly of a cyclic amphiphilic block copolymer, which was prepared by intramolecular metathesis, produced a micelle with an approximately 50 °C increase in thermal stability compared with the one from the linear prepolymer. Single-molecule spectroscopic studies also revealed different diffusion modes for cyclic and linear polymers.