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Water-solubleconducting polymers are of interest to enable moreversatile processing in aqueous media as well as to facilitate interactionswith 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 detachesfrom the underlying electrode. The oxidation of PEDOT-S:H starts withan initial phase of swelling followed by cracking before it finallydisrupts into small flakes and detaches from the electrode. We investigatedthe 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. Whenoxidizing PEDOT-S:H, the positively charged polymer backbone is balancedby anions from the electrolyte solution and also by the sulfonategroups on the side chains (more self-doping). From our experiments,we conclude that detachment of the PEDOT-S:H film upon oxidation occursin part due to swelling caused by an inflow of solvated anions andassociated water and in part due to chain rearrangements within thefilm, caused by more self-doping. We believe that PEDOT-S:H detachmentcan be of interest in a number of different applications, includingaddressed and active control of the release of materials such as biomoleculesand cell cultures. [ABSTRACT FROM AUTHOR]