Effect of (3‐glycidyloxypropyl)trimethoxysilane (GOPS) on the electrical properties of PEDOT:PSS films

• Published in: Journal of polymer science. Part B, Polymer physics Vol. 55; no. 10; pp. 814 - 820
• Main Authors: Håkansson, Anna, Han, Shaobo, Wang, Suhao, Lu, Jun, Braun, Slawomir, Fahlman, Mats, Berggren, Magnus, Crispin, Xavier, Fabiano, Simone
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 15.05.2017
• Subjects: Aqueous environments; Conducting polymers; Crosslinking; Electrical properties; film morphology; GOPS; oxidation level; PEDOT:PSS; Polymeric films; Resistivity; Strategy; Sulfonic acid; GOPS; film morphology; crosslinking; oxidation level; PEDOT:PSS
• ISSN: 0887-6266; 1099-0488; 1099-0488
• DOI: 10.1002/polb.24331

ABSTRACT Poly(3,4‐ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS) has been reported as a successful functional material in a broad variety of applications. One of the most important advantages of PEDOT:PSS is its water‐solubility, which enables simple and environmental friendly manufacturing processes. Unfortunately, this also implies that pristine PEDOT:PSS films are unsuitable for applications in aqueous environments. To reach stability in polar solvents, (3‐glycidyloxypropyl)trimethoxysilane (GOPS) is typically used to cross‐link PEDOT:PSS. Although this strategy is widely used, its mechanism and effect on PEDOT:PSS performance have not been articulated yet. Here, we present a broad study that provides a better understanding of the effect of GOPS on the electrical and electronic properties of PEDOT:PSS. We show that the GOPS reacts with the sulfonic acid group of the excess PSS, causing a change in the PEDOT:PSS film morphology, while the oxidation level of PEDOT remains unaffected. This is at the origin of the observed conductivity changes. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 814–820 The conducting polymer PEDOT:PSS is a useful and well‐studied functional material. This mixed ion‐electron conductor has gained popularity from its water‐solubility which enables simple processing. Unfortunately, this feature implies that the solid structure dissolves when operating in aqueous environments. To avoid this, methoxysilane‐based crosslinkers are often added, making the polymer films water‐stable but also reducing the conductivity significantly. This study helps to understand this crosslinking mechanism and shows how it affects the properties of PEDOT:PSS.