title: Electronic control over detachment of a self-doped water-soluble conjugated polyelectrolyte.
abstract: Water-soluble conducting polymers are of interest to enable more versatile processing in aqueous media as well as to facilitate interactions with biomolecules. Here, we report a substituted poly(3,4-ethylenedioxythiophene) derivative (PEDOT-S:H) that is fully water-soluble and self-doped. When electrochemically oxidizing a PEDOT-S:H thin film, the film detaches from the underlying electrode. The oxidation of PEDOT-S:H starts with an initial phase of swelling followed by cracking before it finally disrupts into small flakes and detaches from the electrode. We investigated the detachment mechanism and found that parameters such as the size, charge, and concentration of ions in the electrolyte, the temperature, and also the pH influence the characteristics of detachment. When oxidizing PEDOT-S:H, the positively charged polymer backbone is balanced by anions from the electrolyte solution and also by the sulfonate groups on the side chains (more self-doping). From our experiments, we conclude that detachment of the PEDOT-S:H film upon oxidation occurs in part due to swelling caused by an inflow of solvated anions and associated water and in part due to chain rearrangements within the film, caused by more self-doping. We believe that PEDOT-S:H detachment can be of interest in a number of different applications, including addressed and active control of the release of materials such as biomolecules and cell cultures.
authors.affiliation: Department of Science and Technology, Linköping University , 601 74 Norrköping, Sweden.
authors.forename: Kristin M
authors.initials: KM
authors.lastname: Persson
authors.forename: Roger
authors.initials: R
authors.lastname: Gabrielsson
authors.forename: Anurak
authors.initials: A
authors.lastname: Sawatdee
authors.forename: David
authors.initials: D
authors.lastname: Nilsson
authors.forename: Peter
authors.initials: P
authors.lastname: Konradsson
authors.forename: Magnus
authors.initials: M
authors.lastname: Berggren
mesh_terms: D000838:Anions; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry; D004563:Electrochemistry; D004566:Electrodes; D004573:Electrolytes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D010100:Oxygen / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D012995:Solubility; D012997:Solvents / Q000737:chemistry; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D000838:Anions; D019086:Bridged Bicyclo Compounds, Heterocyclic; D004573:Electrolytes; D011108:Polymers; D012997:Solvents; C121383:poly(3,4-ethylene dioxythiophene); D014867:Water; D010100:Oxygen