Abstract
Polar polythiophenes with oligoethylene glycol side chains are exceedingly soft materials. A low glass transition temperature and low degree of crystallinity prevents their use as a bulk material. The synthesis of a copolymer comprising 1) soft polythiophene blocks with tetraethylene glycol side chains, and 2) hard urethane segments is reported. The molecular design is contrary to that of other semiconductor-insulator copolymers, which typically combine a soft nonconjugated spacer with hard conjugated segments. Copolymerization of polar polythiophenes and urethane segments results in a ductile material that can be used as a free-standing solid. The copolymer displays a storage modulus of 25 MPa at room temperature, elongation at break of 95%, and a reduced degree of swelling due to hydrogen bonding. Both chemical doping and electrochemical oxidation reveal that the introduction of urethane segments does not unduly reduce the hole charge-carrier mobility and ability to take up charge. Further, stable operation is observed when the copolymer is used as the active layer of organic electrochemical transistors.
| Original language | English (US) |
|---|---|
| Article number | 2002778 |
| Journal | Advanced Science |
| Volume | 8 |
| Issue number | 2 |
| DOIs | |
| State | Published - Jan 20 2021 |
Funding
S.Z. and R.K. contributed equally to this work. The authors gratefully acknowledge financial support from the Swedish Research Council through Grants Nos. 2016‐06146 and 2018‐03824, the Knut and Alice Wallenberg Foundation through a Wallenberg Academy Fellowship, and the European Research Council (ERC) under Grant Agreement No. 637624. WAXS measurements and electron microscopy were performed at the Chalmers Material Analysis Laboratory (CMAL). The authors thank R. B. Rashid for fabricating OECT test chips. B.D.P. and J.R. gratefully acknowledge support from the National Science Foundation Grant No. NSF DMR‐1751308. W.S. gratefully acknowledges support from the Northwestern University Office of Undergraduate Research. This work utilized the Keck‐II facility of Northwestern University's NUANCE Center and the Northwestern University Micro/Nano Fabrication Facility (NUFAB), which are both partially supported by Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS‐1542205), the Materials Research Science and Engineering Center (NSF DMR‐1720139), the State of Illinois, and Northwestern University. Additionally, the Keck‐II facility is partially supported by the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. J.G. and E.S. gratefully acknowledge support from The Wallenberg Wood Science Center (KAW 2018.0452). The authors thank Prof. Enrique Gomez for highly insightful discussions.
Keywords
- chemical and electrochemical doping
- organic electrochemical transistors (OECT)
- polar conjugated polymers
- swelling
- urethane
ASJC Scopus subject areas
- Medicine (miscellaneous)
- General Chemical Engineering
- General Materials Science
- Biochemistry, Genetics and Molecular Biology (miscellaneous)
- General Engineering
- General Physics and Astronomy