具有热可逆选择性反射可见光的自组织超螺旋结构

美国肯特州立大学李全（Quan Li）教授课题组发现了一种在整个可见光波段内都具有选择反射性能的新的超螺旋结构。该结构可在很宽的温度范围内进行调控，反射从紫外到近红外波段的光。

该研究团队认为这种超螺旋结构可用于制备颜色随温度而改变的温度计，同时该研究表明有望通过选择性地掺杂不同组分到某单一体系，以获取具有应用前景的新颖性能。

Source: © Royal Society of Chemistry

Chemicalstructure of the bent-core oligomesogen 1 exhibiting different phases

Liquid crystals are intriguing materials which have properties of both liquids and crystals. They have found uses in many day-to-day applications, such as flat-screen televisions, but much about them, and the many phases they can exhibit, remain unknown.

Quan Li’s group, at State Kent University, had previously designed a new achiral liquid crystal trimer with a twist-bend nematic phase. In this experiment they doped it into a chiral liquid crystal (CLC) to see what effect it would have. As expected, adding the trimer increased the CLC’s chirality, forming a helical structure. More surprisingly, it also increased the temperature range of the liquid crystal phase, proportionally with the concentration of trimer added. What’s more, the resulting superstructure reflected light across the whole visible spectrum. The specific wavelength reflected could be reversibly tuned by adjusting the temperature, meaning the structure could reflect different colours of light at different temperatures.

The group think that strong molecular interactions between the CLC molecule and rod-like units of the trimer cause the effect. In future the superstructure could be used to make colour-display thermometers, and demonstrates the potential of doped liquid crystal systems in obtaining new fascinating properties.

Read abstract of this article:

Thermally reversible full color selective reflection in a self-organized helical superstructure enabled by a bent-core oligomesogen exhibiting a twist-bend nematic phase

Yuan Wang, Zhi-gang Zheng, Hari Krishna Bisoyi, Karla G. Gutierrez-Cuevas, Ling Wang, Rafael S. Zola and Quan Li*

Mater. Horiz., 2016, 3, 442-446

DOI: 10.1039/C6MH00101G

A self-organized helical superstructure was found to exhibit thermally tunable, reversible selective reflection of light across the whole visible region upon doping with an achiral bent-core hybrid trimer having a twist-bend nematic phase.

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