Introduction of Triptycene with a Particular Substitution Pattern into Polymer Chains Can Dramatically Improve the Structural and Rheological Properties.

Although a large number of polymers that contain triptycene units in the main chains have been developed, no polymer design using 1,8-substituted triptycene has been reported to date. In this study, we investigated the properties of linear homo- and copolymers obtained by ring-opening polymerization of a triptycene monomer bearing a macrocyclic olefin linked at its 1,8-position and its copolymerization with cyclooctene, respectively. We found that the introduction of triptycene with this substitution pattern leads to nanoscale molecular ordering, thereby greatly improving the physical properties of the polymers.

Terminal Functionalization with a Triptycene Motif That Dramatically Changes the Structural and Physical Properties of an Amorphous Polymer.

A surprising terminal-group effect on the structural and physical properties of an amorphous polymer is reported. We recently demonstrated that triptycene derivatives with substituents at the 1,8,13-positions show specific self-assembly behavior, enabling the formation of a well-defined "2D + 1D" structure based on nested hexagonal packing of the triptycenes. Upon terminal functionalization with a 1,8-substituted triptycene (1,8-Trip), a liquid polymer, polydimethylsiloxane (PDMS, M = 18-24 kDa), turned into a highly viscous solid that exhibits birefringence at 25 °C.