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Consequences of Chirality in Directing the Pathway of Cholesteric Helix Inversion of π‐Conjugated Polymers by Light
Author(s) -
Kulkarni Chidambar,
Curvers Rick H. N.,
Vantomme Ghislaine,
Broer Dirk J.,
Palmans Anja R. A.,
Meskers Stefan C. J.,
Meijer E. W.
Publication year - 2021
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202005720
Subject(s) - materials science , conjugated system , azobenzene , polymer , circular polarization , supramolecular chirality , chirality (physics) , side chain , photochemistry , mesoscopic physics , fluorene , supramolecular chemistry , chemical physics , crystallography , optics , condensed matter physics , chemistry , chiral symmetry breaking , crystal structure , physics , nambu–jona lasinio model , quantum mechanics , composite material , quark , microstrip
Control over main‐chain motion of chiral π‐conjugated polymers can lead to unexpected new functionalities. Here, it is shown that by combining photoswitchable azobenzene units in conjugation with chiral fluorene comonomers and appropriate plasticizers, the polymer organization and chiroptical properties of these alternating copolymers steered by light and its state of polarization can be dynamically controlled. The configuration of the stereogenic centers in the side chains of the fluorene units determines the handedness of the cholesteric organization in thermally annealed films, indicating cooperative behavior. The polymer alignment and helicity of the supramolecular arrangement can be switched by irradiating with linearly and circularly polarized light, respectively. Intriguingly, when switching the handedness of thermally induced cholesteric organizations by illuminating with circularly polarized light that is opposite to the handedness of the cholesteric phases, a nematic‐like intermediate state is observed during helix interconversion. By the sequence of irradiation with left and right circularly polarized light followed by thermal annealing, an asymmetric motion, reminiscent of that seen in molecular motors is observed. These findings suggest that functional conjugated polymers can exhibit emergent properties at mesoscopic scale.