Light in liquid-crystalline polymers with photoswitchable glass transition

Tinuku - 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.

Researchers reported by incorporating a “photomelting” azobenzene monomer crosslinked into liquid crystalline (LC) networks, generate photoresponsive polymer films that exhibit reversible photoswitchable glass transition temperatures (Tg) at room temperature (~20C) and photomechanical actuations under the stimulus of UV/visible light.

Tinuku Light in liquid-crystalline polymers with photoswitchable glass transition

The trans-to-cis isomerization of azo chromophores results in a change in Tg of the crosslinked LC polymers. The Tg of the polymer network is higher than room temperature in the trans-form and lower than room temperature in the cis-form. The team reported to Nature Communications.



“We demonstrate the photoswitchable Tg contribute to the photomechanical bending and a new mechanism for photomechanical bending that attributes the process to an inhomogeneous change in Tg of the film is proposed,“ said Youfeng Yue of the National Institute of Advanced Industrial Science and Technology (AIST) in Ibaraki.

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