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Probing the Viscoelastic Property of Pseudo Free‐Standing Conjugated Polymeric Thin Films
Author(s) -
Zhang Song,
Ocheje Michael U.,
Luo Shaochuan,
Ehlenberg Dakota,
Appleby Benjamin,
Weller Daniel,
Zhou Dongshan,
RondeauGagné Simon,
Gu Xiaodan
Publication year - 2018
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201800092
Subject(s) - viscoelasticity , materials science , polymer , conjugated system , glass transition , stress relaxation , polymer chemistry , acceptor , thin film , composite material , hysteresis , chemical engineering , nanotechnology , creep , condensed matter physics , physics , engineering
The understanding of the structure‐mechanical property relationship for semiconducting polymers is essential for the application of flexible organic electronics. Herein pseudo free‐standing tensile testing, a technique that measures the mechanical property of thin films floating on the surface of water, is used to obtain the stress–strain behaviors of two semiconducting polymers, poly(3‐hexylthiophene) (P3HT) and poly(2,5‐bis(2‐decyltetradecyl)‐3,6‐di(thiophen‐2‐yl)diketopyrrolo[3,4‐c]pyrrole‐1,4‐dione‐ alt ‐thienovinylthiophene (DPP‐TVT) donor–acceptor (D–A) polymer. To our surprise, DPP‐TVT shows similar viscoelastic behavior to P3HT, despite DPP‐TVT possessing a larger conjugated backbone and much higher charge carrier mobility. The viscoelastic behavior of these polymers is due to sub room temperature glass transition temperatures ( T g ), as shown by AC chip calorimetry. These results provide a comprehensive understanding of the viscoelastic properties of conjugated D–A polymers by thickness‐dependent, strain rate dependent, hysteresis tests, and stress‐relaxation tests, highlighting the importance of T g for designing intrinsically stretchable conjugated polymers.