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- Gu, Modi, et al.
(author)
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Molecular design of an electropolymerized copolymer with carboxylic and sulfonic acid functionalities
- 2022
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In: Synthetic metals. - : Elsevier BV. - 0379-6779 .- 1879-3290. ; 285, s. 117029-
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Journal article (peer-reviewed)abstract
- Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is the most researched conjugated polymer in the field of organic bioelectronics. The conjugated PEDOT backbone features good redox stability in aqueous electrolyte, and low oxidation potential. However, PEDOT:PSS has two major drawbacks. The PEDOT backbone lacks biofunctionality, limiting the fine tuning of its interface with the biological environment. The dopant PSS is insulating, resulting in a decrease in the capacitance of the polymer. Here, we describe the design of a random copolymer, P(EDOTCOOH-co-EDOTS), based on EDOT monomers functionalized with sulfonic and carboxylic acid groups. The copolymer was successfully synthesized by electropolymerization as confirmed by X-ray photoelectron spectroscopy. Contact angle measurements illustrated the high hydrophilicity of the P (EDOTCOOH-co-EDOTS) (28 & PLUSMN; 6 & nbsp;), attributed to the sulfonate group in the side chains. This in turn led to a higher water penetration into the copolymer film, enhancing significantly its volumetric capacitance (69 & PLUSMN; 4 F cm(-3)), and thereby, its performance when used as an active channel in an organic electrochemical transistor. Of note, we incorporated the sulfonate group in its sodium salt form retaining its highly ionized properties. This is the first instance of utilizing an uncapped, ionized sulfonate group covalently bound to the backbone of a polymer, where the resultant polymer is oxidized at very low potentials, as well as stable and electroactive in aqueous electrolytes. Furthermore, our molecular design to incorporate carboxylic acid groups paves the way for the development of conjugated polymers that can be tailored for bioelectronic applications.
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| 3. |
- Wu, Jiaxin, et al.
(author)
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Organic Mixed Ionic–Electronic Conductors Based on Tunable and Functional Poly(3,4-ethylenedioxythiophene) Copolymers
- 2024
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In: ACS Applied Materials and Interfaces. - 1944-8244 .- 1944-8252. ; 16:22, s. 28969-28979
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Journal article (peer-reviewed)abstract
- Organic mixed ionic–electronic conductors (OMIECs) are being explored in applications such as bioelectronics, biosensors, energy conversion and storage, and optoelectronics. OMIECs are largely composed of conjugated polymers that couple ionic and electronic transport in their structure as well as synthetic flexibility. Despite extensive research, previous studies have mainly focused on either enhancing ion conduction or enabling synthetic modification. This limited the number of OMIECs that excel in both domains. Here, a series of OMIECs based on functionalized poly(3,4-ethylenedioxythiophene) (PEDOT) copolymers that combine efficient ion/electron transport with the versatility of post-functionalization were developed. EDOT monomers bearing sulfonic (EDOTS) and carboxylic acid (EDOTCOOH) groups were electrochemically copolymerized in different ratios on oxygen plasma-treated conductive substrates. The plasma treatment enabled the synthesis of copolymers containing high ratios of EDOTS (up to 68%), otherwise not possible with untreated substrates. This flexibility in synthesis resulted in the fabrication of copolymers with tunable properties in terms of conductivity (2–0.0019 S/cm) and ion/electron transport, for example, as revealed by their volumetric capacitances (122–11 F/cm3). The importance of the organic nature of the OMIECs that are amenable to synthetic modification was also demonstrated. EDOTCOOH was successfully post-functionalized without influencing the ionic and electronic transport of the copolymers. This opens a new way to tailor the properties of the OMIECs to specific applications, especially in the field of bioelectronics.
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