Solvent-Free Photoresponsive Artificial Muscles Rapidly Driven by Molecular Machines,Journal of the American Chemical Society

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Solvent-Free Photoresponsive Artificial Muscles Rapidly Driven by Molecular Machines
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2018-11-11 , DOI: 10.1021/jacs.8b11351
Shinji Ikejiri ₁ , Yoshinori Takashima _{1,

2} , Motofumi Osaki ₁ , Hiroyasu Yamaguchi ₁ , Akira Harada _{1,

3}

Affiliation

We prepared photoresponsive actuators as both hydrogels and dry gels consisting of 4-arm poly(ethylene glycol) (PEG) cross-linked by a [c2]daisy chain, which is a double-threaded [2]rotaxane dimer with α-cyclodextrin (αCD) and stilbene. The obtained gels showed fast and large deformation triggered by UV irradiation in both wet and dry states. The UV/vis spectroscopy results, NMR measurements and tensile tests on the gels revealed that the actuation is driven by photoisomerization of the stilbene unit in the [c2]daisy chain. The responsiveness of these gels depends on the molecular weight of the 4-arm PEG. These results suggest that αCD recognizes trans-stilbene prior to UV irradiation to maintain the length of the PEG chain in the polymer network and that photoisomerization allows αCD to leave the cis-stilbene moiety and move onto the PEG chain because the association constant of αCD with cis-stilbene is quite low. Thus, the sliding motion of the αCD unit shrinks the [c2]daisy chain, leading to the contraction of the gels. In both wet and dry states, these actuations are repeatable through reversible photoisomerization of the stilbene moiety using different wavelengths of UV-light irradiation and can be used to perform bending and lifting actions (for 15 times heavier weight compared to the dry gel).

中文翻译：

由分子机器快速驱动的无溶剂光响应人工肌肉

我们将光响应致动器制备为水凝胶和干凝胶，它们由通过 [c2] 菊花链交联的 4 臂聚（乙二醇）（PEG）组成，这是一种带有 α-环糊精的双线 [2] 轮烷二聚体（ αCD) 和芪。获得的凝胶在湿态和干态下均显示出由紫外线照射引发的快速和大的变形。凝胶的紫外/可见光谱结果、核磁共振测量和拉伸测试表明，驱动是由 [c2] 菊花链中二苯乙烯单元的光异构化驱动的。这些凝胶的响应性取决于 4 臂 PEG 的分子量。这些结果表明 αCD 在紫外线照射前识别反式二苯乙烯以维持聚合物网络中 PEG 链的长度，并且光异构化允许 αCD 离开顺式二苯乙烯部分并移动到 PEG 链上，因为 αCD 与顺二苯乙烯相当低。因此，αCD 单元的滑动使 [c2] 菊花链收缩，导致凝胶收缩。在湿态和干态下，通过使用不同波长的紫外光照射二苯乙烯部分的可逆光异构化，这些驱动是可重复的，并可用于执行弯曲和提升动作（与干凝胶相比，重量重 15 倍）。导致凝胶收缩。在湿态和干态下，通过使用不同波长的紫外光照射二苯乙烯部分的可逆光异构化，这些驱动是可重复的，并可用于执行弯曲和提升动作（与干凝胶相比，重量重 15 倍）。导致凝胶收缩。在湿态和干态下，通过使用不同波长的紫外光照射二苯乙烯部分的可逆光异构化，这些驱动是可重复的，并可用于执行弯曲和提升动作（与干凝胶相比，重量重 15 倍）。

更新日期：2018-11-11

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