Cyclic polymers: past, present and future

Abstract

Abstract Methods for characterising cyclic polymers are illustrated by reference first to dilute solution methods for cyclic poly(dimethylsiloxane) (PDMS) and then to the entrapment of cyclic polymers in networks. Preparative routes to cyclic polymers are then reviewed, including ring‐chain equilibration reactions, coupling and condensation reactions and new methods using polymer‐supported reagents. Some of the properties of cyclic PDMS are discussed, including differences between ring and chain polymer properties such as their melt viscosities and glass transition temperatures. Methods for preparing the first polymeric catenanes are described, using polymer‐supported reagents. Future directions for cyclic polymer chemistry are indicated, including topological polymer chemistry.