Photomechanical molecular crystals and nanowire assemblies based on the [2+2] photodimerization of a phenylbutadiene derivative
Photomechanical molecular crystals and nanowire assemblies based on the [2+2] photodimerization of a phenylbutadiene derivative
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DOI：
10.1039/c9tc06946a
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发表时间：
2020-04
影响因子：
6.4
通讯作者：
Fei Tong;Wenwen Xu;Tianyi Guo;Brandon F. Lui;R. Hayward;P. Palffy-Muhoray;R. Al‐Kaysi;C. Bardeen
中科院分区：
文献类型：
--
作者：
Fei Tong;Wenwen Xu;Tianyi Guo;Brandon F. Lui;R. Hayward;P. Palffy-Muhoray;R. Al‐Kaysi;C. Bardeen
（E）-4-氟-肉桂醛丙二腈（（E）-4FCM）是一种新的苯基丁二烯衍生物，它以晶体形式存在，经过[2+2]光环合反应。光吸收和质子核磁共振（1H-NMR）测量表明，固态（E）-4FCM光二聚反应是一个负的光致变色反应，进行到97%完成。当暴露于405 nm紫外光时，大的几何形状变化和完全转化允许（E）-4FCM的块状晶体显示出强的光显效应。当（E）-4FCM纳米线在阳极氧化铝（AAO）模板中生长时，它们保持高度的结晶度和取向，如通过X射线衍射测量所确定的。当被照射时，（E）-4FCM纳米线束表现出快速膨胀，在此期间它们在横向方向上扩展多达300%。这种横向膨胀至少部分是由于光致晶体沿着纳米线直径沿着膨胀。当（E）-4FCM纳米线被限制在AAO模板内时，光致膨胀可被利用以使模板变形，从而导致其在UV光照射下弯曲。模板中2.0 mg 4FCM引起的弯曲运动可导致模板弯曲高达1.0 mm，并提升高达200 g。这些结果代表了一个显着的改善，在工作输出相对于以前的复合致动器膜的基础上二芳基乙烯光致变色剂。
(E)-4-Fluoro-cinnamaldehyde malononitrile ((E)-4FCM) is a new phenylbutadiene derivative that undergoes a [2+2] photocycloaddition in the crystal form. Optical absorption and proton nuclear magnetic resonance (1H-NMR) measurements demonstrate that the solid-state (E)-4FCM photodimerization is a negative photochromic reaction that proceeds to 97% completion. The large geometry change and full conversion allow bulk crystals of (E)-4FCM to show strong photosalient effects when exposed to 405 nm ultraviolet light. When (E)-4FCM nanowires are grown in an anodic alumina oxide (AAO) template, they maintain a high degree of crystallinity and orientation, as determined by X-ray diffraction measurements. When illuminated, (E)-4FCM nanowire bundles exhibit a rapid expansion, during which they spread by as much as 300% in the lateral direction. This lateral expansion is at least partially due to a photoinduced crystal expansion along the diameter of the nanowires. When (E)-4FCM nanowires are confined inside the AAO template, the photoinduced expansion can be harnessed to deform the template, causing it to bend under UV light irradiation. The bending motion due to 2.0 mg of 4FCM in a template can cause the template to bend by up to 1.0 mm and lift up to 200 g. These results represent a significant improvement in work output relative to previous composite actuator membranes based on diarylethene photochromes.