Polydiacetylene/ZnO Nanocomposite Films for Voltage-Responsive Electrochromatic Applications

Polydiacetylene (PDA) undergoes color transitions in response to external stimuli. Here, ZnO nanorods (ZnO-NRs) were used as a high-surface-area scaffold to enhance charge transport and support PDA self-assembly. The PDA/ZnO nanocomposites exhibited an irreversible blue-to-red transition under a low applied potential (<0.4 V) in the presence of [Fe(CN)₆]³⁻/⁴⁻, with the λmax shifting from ∼646 nm to ∼550 nm, accompanied by Raman shifts of C═C and C≡C modes. This electrochromatic response arises from electric-field-induced backbone conformational changes promoted by side-chain disorder, which shortens the effective π-conjugation length, highlighting the potential of these nanocomposites for single-use electrochromatic sensors.