Polysemiins

Polysemiins are a class of polymers defined by an alternating architecture of semi-conjugated conductive segments and insulating spacers within the polymer backbone. This arrangement aims to combine features of conjugated polymers, such as tunable optical absorption and charge-delocalization, with the high dielectric performance and environmental stability of insulating polymers. The result is materials with tunable dielectric constants, breakdown strength, and processability, potentially suitable for flexible electronics and photonics.

The backbone includes repeating units that provide partial pi-conjugation, interspersed with insulating moieties that disrupt full conjugation to control conductivity and dielectric behavior. Properties depend on the fraction of conductive units, molecular weight, tacticity, and side-chain chemistry. They may exhibit adjustable band gaps and dielectric constants, and can be processed from solution.

Synthesis of polysemiins typically involves step-growth or polycondensation polymerizations using monomers that bear semi-conjugated cores and insulating linkers, along with cross-coupling or click-chemistry to assemble. Control of sequencing and block architectures allows tuning of material properties and processability.

Applications for polysemiins are envisioned in dielectric layers for flexible displays, organic field-effect transistors, photovoltaic interlayers, and energy storage devices, where the combination of semiconducting and insulating features can be advantageous. They may also enable sensors in which dielectric environments modulate optical or electronic responses.

Research status and outlook: The concept remains under investigation, with key challenges including achieving uniform sequence control, minimizing defect-induced leakage, ensuring environmental stability, and developing scalable synthesis routes. Ongoing work focuses on defining structure–property relationships and identifying practical processing methods.

See also: Conjugated polymers, polymer dielectrics, electronically active polymers, hybrid polymers.