Controlling the doping states of conjugated poly(N-vinyl carbazole) (PVK) nanofibers have been observed to facilitate extreme color changes and notable wetting properties. As produced via electrostatic spinning, the PVK nanofibers with individual diameters of 380-660 nm, are randomly oriented in the surface whose nanoscale roughness combined with the material's inherent hydrophobicity resulted to a superhydrophobic coating with water contact angles (WCA) reaching 151.040. Unlike other superhydrophobic coatings, the resulting anti-wetting film demonstrates high adhesion towards the water droplet (pinning effect), which has potential applications for non-loss fluid transportation, in-situ localized chemical reactions or oil-water separation. Furthermore, the oxidation state of conjugated polymers like polycarbazoles, polythiophenes, polypyrrole and polyaniline can be tuned through solid-state oxidation/reduction reactions or electrochemistry. By switching the doping state of these polymers, distinct property changes such as color change, conductivity, and wettability can be observed. Oxidizing the PVK fiber mats using low Fe3+ concentrations changed the color from white to green, which can be reversed by exposing the doped PVK fiber mats to small amounts of hydrazine. Moreover, the wettability of the fibers can be tuned depending on the amount of dopant/reductant used. With these properties, the PVK fiber mats can potentially be used for developing chromic displays, sensors, and biological membrane separation.

Redox-responsive chromism and wetting properties of PVK nanofibers

246th National Meeting (2013)

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