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Light-induced mechanical response in crosslinked liquid-crystalline polymers with photoswitchable glass transition temperatures

Energy conversion of light into mechanical work is of fundamental interest in applications. In particular, diligent molecular design on nanoscale, in order to achieve efficient photomechanical effects on macroscopic scale, has become one of the most interesting study topics. Here, by incorporating a...

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Detalles Bibliográficos
Autores principales: Yue, Youfeng, Norikane, Yasuo, Azumi, Reiko, Koyama, Emiko
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6089925/
https://www.ncbi.nlm.nih.gov/pubmed/30104602
http://dx.doi.org/10.1038/s41467-018-05744-x
Descripción
Sumario:Energy conversion of light into mechanical work is of fundamental interest in applications. In particular, diligent molecular design on nanoscale, in order to achieve efficient photomechanical effects on macroscopic scale, has become one of the most interesting study topics. Here, by incorporating a “photomelting” azobenzene monomer crosslinked into liquid crystalline (LC) networks, we generate photoresponsive polymer films that exhibit reversible photoswitchable glass transition temperatures (T(g)) at room temperature (~20 °C) and photomechanical actuations under the stimulus of UV/visible light. The trans-to-cis isomerization of azo chromophores results in a change in T(g) of the crosslinked LC polymers. The T(g) of the polymer network is higher than room temperature in the trans-form and lower than room temperature in the cis-form. We demonstrate the photoswitchable T(g) contribute to the photomechanical bending and a new mechanism for photomechanical bending that attributes the process to an inhomogeneous change in T(g) of the film is proposed.