Reviews & Analysis

Triptycene-containing polymers featuring a rigid propeller-shaped structure have attracted attention for a wide range of potential applications including guest recognition, material transports, separations, catalysis, and organic electronics. Herein, with a thorough literature survey, we present the synthesis of the various types of triptycenes that provide components for functional polymers. We particularly focus on triptycene-containing polymers and two-dimensional assemblies based on the space-filling design that uses nested packing. Future perspectives on the functionalities brought about by the design of triptycene-containing polymers and molecular assemblies are also discussed.

Photoinduced transitions between the solid, glass, and liquid states based on molecular photoswitches promise an enormous variety of applications, such as photoswitchable adhesives, which contribute to material recycling for a sustainable future in the era of composite materials. In this review, we highlight recent progress in the photoinduced transitions of small molecules and polymers and systematically discuss the molecular designs, mechanisms, applications, merits and demerits, and future challenges in each photoswitch and the whole field.

Mechanochemistry is a promising technology to tackle current and future polymer waste streams for a sustainable future. With this review, we take into account synthetic, computational, technical, and engineering perspectives to converge trituration and polymer mechanochemistry with a particular focus on the fate of commodity polymers and potential technologies to monitor mechanochemical reactions while they occur. We highlight the need for future transdisciplinary research to tackle the high-leverage parameters governing an eventually successful mechanochemical polymer degradation approach for a circular economy.