Multiresponsive PEDOT–Ionic Liquid Materials for the Design of Surfaces with Switchable Wettability

Abstract

Among the different types of stimuli‐responsive polymers, conjugated polymers reveal unique multiresponsive behavior. In this work, the synthesis and characterization of new functional poly(3,4‐ethylenedioxythiophenes) (PEDOT) bearing imidazolium ionic‐liquid moieties (PEDOT‐Im) is reported. PEDOT‐Im polymers show multiresponsive properties to a variety of stimuli, such as temperature, pH, oxidative doping, and presence of anions. These stimuli provoke different changes in PEDOT‐Im, such as changes in color, oxidation state, and, wetting behavior. In all cases, a reversible effect is observed, and the polymers reveal responsive properties in solution as well as in the form of thin films. Whereas sensitiveness to pH and oxidative doping are known phenomena for other PEDOT derivatives, responsiveness to temperature and to anions is a unique property of PEDOT‐Im. The anion exchange is further investigated by means of the Quartz Crystal Microbalance with dissipation. Anion exchanges induce fast, adjustable, and reversible contact angle changes between 24° and 107°. As a potential application, surfaces with switchable wettability triggered by anion solutions are prepared by spin‐coating PEDOT‐Im films onto different substrates.

Significant Enhancement of PEDOT Thin Film Adhesion to Inorganic Solid Substrates with EDOT-Acid

“…30 After the initial equilibration step with pure ethanol, introduction of the EDOTacid solution (point A in Figure S1) caused a sudden drop in the resonant frequency signal, followed by a slower frequency decrease. The whole adsorption lasted for 15 minutes until it reached an steady state.…”

Tunable conjugated polymers for bacterial differentiation

“…For our purposes, the wettability of the polymer surfaces could be controlled by using an appropriate dopant and the redox state conditions [21,22,68]. Roughness is described as the typical height variation on the surface.…”

Novel multi-responsive polymer materials: When ionic liquids step in

“…They also synthesized a poly(NIPAM-co-EVImBr) with temperature and ion responsive properties based on IL, 1-ethyl-3-vinylimidazolium bromide [41]. The strong polarization interactions of ILs can be used to disperse the carbon nanotubes grafted with imidazolium IL (PEDOT-Im) groups, exhibiting response to temperature, pH, oxidative doping, and presence of anions, which caused the changes in color, oxidation state, and wetting behavior [43]. The PEDOT-Im reveals a unique temperature and anion-responsive properties.…”