Hydrophobic poly(3,4-ethylenedioxythiophene) particles synthesized by aqueous oxidative coupling polymerization and their use as near-infrared-responsive liquid marble stabilizer

The aqueous oxidative coupling polymerization of 3,4-ethylenedioxythiophene was conducted in the presence of heptadecafluorooctane sulfonic acid, which was used as a perfluoroalkyl dopant to synthesize hydrophobic poly(3,4-ethylenedioxythiophene) particles. The poly(3,4-ethylenedioxythiophene) particles were characterized in terms of their size, morphology, surface and bulk chemical compositions, conductivity, hydrophilic–hydrophobic balance and (photo)thermal properties. The electron microscopy studies confirmed that poly(3,4-ethylenedioxythiophene) consisted of aggregates of primary atypical particles of a submicrometer size. X-ray photoelectron spectroscopy and the contact angle measurement indicated that the perfluoroalkyl dopants were present on the surface of the poly(3,4-ethylenedioxythiophene) particles, which caused them to have a hydrophobic character. The electrical conductivity of the pressed pellet was 15.5？S？cm？1, which was one order of magnitude higher than that of the poly(3,4-ethylenedioxythiophene) that was synthesized in the absence of the perfluoroalkyl dopant. The dried poly(3,4-ethylenedioxythiophene) particles could be used as a near-infrared-responsive liquid marble stabilizer exhibiting light-to-heat conversion properties. The movement of the poly(3,4-ethylenedioxythiophene) particle-coated liquid marbles on a planar water surface was driven by near-infrared laser-induced Marangoni propulsion. The inner liquid could be released by the disruption of the liquid marbles via an application of an external stimulus