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Toward the Prediction and Control of Glass Transition Temperature for Donor–Acceptor Polymers
Author(s) -
Zhang Song,
Alesadi Amirhadi,
Selivanova Mariia,
Cao Zhiqiang,
Qian Zhiyuan,
Luo Shaochuan,
Galuska Luke,
Teh Catherine,
Ocheje Michael U.,
Mason Gage T.,
St. Onge P. Blake J.,
Zhou Dongshan,
RondeauGagné Simon,
Xia Wenjie,
Gu Xiaodan
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202002221
Subject(s) - materials science , polymer , glass transition , flexibility (engineering) , side chain , acceptor , dynamic mechanical analysis , elastic modulus , composite material , modulus , conjugated system , chemical physics , thermodynamics , condensed matter physics , statistics , physics , mathematics
Semiconducting donor–acceptor (D–A) polymers have attracted considerable attention toward the application of organic electronic and optoelectronic devices. However, a rational design rule for making semiconducting polymers with desired thermal and mechanical properties is currently lacking, which greatly limits the development of new polymers for advanced applications. Here, polydiketopyrrolopyrrole (PDPP)‐based D–A polymers with varied alkyl side‐chain lengths and backbone moieties are systematically designed, followed by investigating their thermal and thin film mechanical responses. The experimental results show a reduction in both elastic modulus and glass transition temperature ( T g ) with increasing side‐chain length, which is further verified through coarse‐grained molecular dynamics simulations. Informed from experimental results, a mass‐per‐flexible bond model is developed to capture such observation through a linear correlation between T g and polymer chain flexibility. Using this model, a wide range of backbone T g over 80 °C and elastic modulus over 400 MPa can be predicted for PDPP‐based polymers. This study highlights the important role of side‐chain structure in influencing the thermomechanical performance of conjugated polymers, and provides an effective strategy to design and predict T g and elastic modulus of future new D–A polymers.