Mono- and Multilayers of Oligoethylene Oxide-Modified Poly(3,4-ethylenedioxythiophene) on ITO and Glass Surfaces Gianni Zotti,* Sandro Zecchin, Gilberto Schiavon, and Barbara Vercelli Istituto CNR per l’ Energetica e le Interfasi, C.o Stati Uniti 4, 35127 Padova, Italy L. “Bert” Groenendaal AGFA-Gevaert N.V., R&D MaterialssChemistry Department, Septestraat 27, B-2640 Mortsel, Belgium Received January 14, 2003. Revised Manuscript Received March 27, 2003 Dichloromethane-soluble poly(3,4-ethylenedioxythiophene)s modified with oligoethylene oxide chains of different lengths (PEDT-EO and PEDT-PEO) were produced by anodic coupling. PEDT-EO solutions were used to produce mono- and multilayer films on ITO- glass electrodes and float glass sheets. Layer-by-layer alternation of doped PEDT-EO with poly(p-styrene sulfonate) (PSS) or doped poly(3,4-ethylenedioxythiophene) sulfonate produced electroactive and robust multilayered surfaces with low surface resistivity (5 × 10 5 Ω/0 for a PEDT-EO/PSS 10-bilayer). Analogous multilayers could be built from doped PEDT-EO and polyammonium polycations. Doped PEDT-EO forms with PSS the first reported electrostatically bound polyionic multilayers in which the positive charge is delocalized over a polythiophene backbone. 1. Introduction Since the discovery that π-conjugated polymers can be electrically conductive, 1 this part of polymer chem- istry has grown enormously. 2 This has resulted in the fact that the Nobel Prize for Chemistry in 2000 was awarded to its pioneers 3 as well as the fact that several applications based on conductive polymers have been commercialized. One of the main (volume-wise) applica- tions nowadays is the use of the conductive polymer poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) (PEDT/PSS) as an antistatic material (antistatic means that the surface resistivity is in the range of 10 6 -10 9 Ω/0). 4 Examples of antistatic PEDT/PSS-based layers can be found in photographic film from AGFA (on PET) and in modern TV screens (on glass). Because of the large areas, antistatic materials are one of the main applications for conductive polymers. Thus, quite a lot of research and development is being performed on this topic in academia and industry. One of the concepts that has been studied frequently over the past years concerns the self-assembly of poly- conjugated polymers as multilayers on surfaces. 5-15 Multilayer films have been prepared through a film deposition technique that utilizes the electrostatic at- traction of oppositely charged polyelectrolytes to create thin films with a layer-by-layer (LBL) technique. The electrostatic multilayer adsorption of positive and nega- tive polyelectrolytes has been widely exploited as an alternative method to the Langmuir-Blodgett tech- nique. This method provides a simple means of deposit- * Corresponding author. Tel.: (39)049-829-5868. Fax: (39)049-829- 5853. E-mail g.zotti@ieni.cnr.it. (1) Shirakawa, H.; Louis, F.J.; MacDiarmid, A.G.; Chiang, C.K.; Heeger, A.J. J. Chem. Soc., Chem. Commun. 1977, 578. (2) For more detailed information on all aspects of conductive polymers, see: (a) Handbook of Conducting Polymers, 2nd ed.; Skotheim, T. A., Elsenbaumer, R. L., Reynolds, J. R., Eds.; Marcel Dekker: New York, 1998. (b) Handbook of Organic Conductive Molecules and Polymers; Nalwa, H. S., Ed.; John Wiley & Sons: Chichester, 1997; Vols. 1-4. (c) Feast, W. J.; Tsibouklis, J.; Pouwer, K. L.; Groenendaal, L.; Meijer, E. W. Polymer 1996, 37, 5017. (d) Stenger-Smith, J. D. Prog. Polym. Sci. 1998, 23, 57. (e) Epstein, A. 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