A template-free approach to nanotube-decorated polymer surfaces using 3,4-phenylenedioxythiophene (PhEDOT) monomers
In this work, novel 3,4-phenylenedioxythiophene (PhEDOT) monomers with alkyl, branched, and aromatic substituents were synthesized and tested for their efficacy at forming surfaces with unique wetting properties and surface morphology without the aid of surfactants. Monomers with a naphthalene substituent clearly showed the highest capacity to stabilize gas bubbles (O2 or H2) formed in solution during electrodeposition from trace water, resulting in the formation of nanotubes. Variation in the resulting density, diameter, and height of nanotubes was demonstrated by varying the electropolymerization protocol, conditions, or electrolyte used. The wetting induced by the nanotube formation results in the surfaces formed having both high contact angles with water (θW) and strong adhesion, despite all polymers being intrinsically hydrophilic. This one-step and easily tunable approach to nanotube formation has potential to advance applications in membrane design, water transport and harvesting, as well as sensor design.