Triphenylene-containing trifluorovinyl ether monomers prepared from 2,3-disubstituted-bis-1,4-(p-bromophenyl)triphenylene core building blocks undergo thermal step-growth polymerization (Ph 2 O, 180 °C), affording perfluorocyclobutyl polymers with unprecedented glass-transition temperatures (up to 295 °C), excellent high thermal-oxidative stabilities, and solution processability. The modular synthetic route provides access to a series of triphenylene monomers from a common cyclopentadienone derivative and variably substituted alkynes, which polymerize thermally to solution-processable, tough, transparent films with bright blue solid-state photoluminescence (λ em = ∼400−470 nm). Conversion was monitored by 19 F NMR end-group analysis and gel permeation chromatography to reasonably high molecular weights (M n = 45−93 kDa). Remarkably, photoemission persists at 250 °C in air for 24 h with negligible changes in absorbance and emission wavelengths after cooling to room temperature.

Many desirable characteristics of polymers arise from the method of polymerization and structural features of their repeat units, which typically are responsible for the polymer’s performance at the cost of processability. While linear alternatives are popular, polymers composed of cyclic repeat units across their backbones have generally been shown to exhibit higher optical transparency, lower water absorption, and higher glass transition temperatures. These specifically include polymers built with either substituted alicyclic structures or aromatic rings, or both. In this review article, we highlight two useful ring-forming polymer groups, perfluorocyclobutyl (PFCB) aryl ether polymers and ortho-diynylarene- (ODA) based thermosets, both demonstrating outstanding thermal stability, chemical resistance, mechanical integrity, and improved processability. Different synthetic routes (with emphasis on ring-forming polymerization) and properties for these polymers are discussed, followed by their relevant applications in a wide range of aspects.

No abstract