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Hierarchical Twist
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Orientador(es)
Resumo(s)
One of the unresolved aspects of cellulose-based liquid crystalline phases is their chirality. Although cellulose is intrinsically chiral, both left-handed (LH) and right-handed (RH) chiral nematic phases are reported in cellulose derivatives under different conditions. The origin of these discrepancies—and whether LH and RH twisted structures coexist within a single material—has remained unclear. Here, the first direct evidence of hierarchical LH and RH twisted structures coexisting in a solvent-free, thermotropic cellulose derivative at room temperature is provided. Free-standing cholesteric films exhibit distinct LH and RH twisted domains, whose pitches respond oppositely to uniaxial mechanical strain: the LH pitch increases, while the RH pitch decreases with increasing strain. This contrasting response results from the coexistence of intertwined LH and RH twisted structures, whose optical axes are oriented differently relative to the strain direction. Notably, after stretching beyond their elastic limit, the films spontaneously recover their original shape within minutes. During this recovery, circular dichroism (CD) measurements reveal an increase in RH pitch and a decrease in LH pitch, evidencing reversible, strain-responsive behavior. Multiscale structural characterization confirms the hierarchical chiral organization and its mechanoresponsive nature, providing new insights into the origin of chirality in cellulose-based liquid crystalline materials.
Descrição
Funding information:
This work has been supported by the ERC H2020 Synergy grant 101167171(ALCEMIST), FCT – Fundação para a Ciência e a Tecnologia, I.P.,in the scope of the projects LA/P/0037/2020, UIDP/50025/2020, and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostruc-tures, Nanomodelling and Nanofabrication i3N. European Cooperationin Science and Technology (COST) Action understanding interaction light– biological surfaces: the possibility for new electronic materials and de-vices (PhoBioS, CA21159). The authors gratefully acknowledge the valu-able, inspiring, and insightful discussions with Randall Kamien and FrankGiesselmann
Publisher Copyright:
© 2025 The Author(s). Advanced Optical Materials published by Wiley-VCH GmbH.
Palavras-chave
chiral nematic liquid crystals hierarchical twisted supramolecular structures mechanoresponsive materials thermotropic cellulose derivatives Electronic, Optical and Magnetic Materials Atomic and Molecular Physics, and Optics