Polyarylene

Polyarylene is a broad class of polymers in which the repeating units contain arylene groups, such as phenylene or naphthylene, and are linked together primarily by carbon–carbon bonds between rings. The aryl rings impart rigidity and thermal stability to the chain, often resulting in high glass transition temperatures and chemical resistance. Architectures range from linear chains to crosslinked networks, and substituents or different linkers can tune properties and processability. Common subfamilies include polyphenylene derivatives and polyarylene ethers or sulfides, such as poly(p-xylylene) (parylene) and polyphenylene sulfide (PPS).

Synthesis and processing of polyarylene materials vary by structure. Routes include high-temperature polycondensation of aryl monomers, oxidative coupling of diaryl precursors, and metal-catalyzed cross-coupling to form aryl–aryl bonds. A notable example is poly-para-xylylene, produced by chemical vapor deposition from the di-p-xylylene dimer, which yields conformal, thin-film coatings. The rigid backbones often lead to poor solubility and limited melt processing, prompting development of derivatives with heteroatoms or flexible linkers to improve processability.

Applications of polyarylene polymers leverage their thermal stability and chemical resistance. They are studied for high-temperature structural materials, membranes, and electronic components. Parylene coatings provide conformal protective layers in electronics, medical devices, and corrosion protection, while PPS and related polyarylene sulfides are used in chemical processing equipment and automotive components. Overall, the polyarylene class emphasizes durable, high-performance materials, with ongoing research aimed at balancing strength, stability, and manufacturability.