Morphological Transitions of a Photoswitchable Aramid Amphiphile Nanostructure
Morphological Transitions of a Photoswitchable Aramid Amphiphile Nanostructure
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DOI：
10.1021/acs.nanolett.0c05048
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发表时间：
2021-03-18
期刊：
影响因子：
10.8
通讯作者：
Ortony, Julia H.
中科院分区：
文献类型：
--
作者：
Kim, Dae-Yoon;Christoff-Tempesta, Ty;Ortony, Julia H.
两亲性小分子在水中的自组装可以导致具有原始内部分子组织的不同几何形状的纳米结构。在这里，我们介绍了一种光开关芳族聚酰胺两亲物（AA），旨在表现出广泛的氢键和强大的机械性能后，自组装，同时含有乙烯基腈基团的光诱导顺反异构化。我们证明了自发自组装的乙烯基腈含AA在水中形成纳米带。在UV照射下，反式到顺式异构化伴随着从纳米带到纳米管的形态转变而发生。这种纳米管结构在水中可以持续六个多月，通过强烈的集体分子间相互作用而稳定。我们证明了纳米带到纳米管的转变在加热时是可逆的，并且可以重复地实现状态之间的切换。最后，我们用电子显微镜捕捉过渡和提出机制nanoribbon纳米管重排，反之亦然。光响应AA纳米结构的稳定性和可切换性使它们在未来的应用中变得可行。
Self-assembly of small amphiphilic molecules in water can lead to nanostructures of varying geometries with pristine internal molecular organization. Here we introduce a photoswitchable aramid amphiphile (AA), designed to exhibit extensive hydrogen bonding and robust mechanical properties upon self-assembly, while containing a vinylnitrile group for photoinduced cis-trans isomerization. We demonstrate spontaneous self-assembly of the vinylnitrile-containing AA in water to form nanoribbons. Upon UV irradiation, trans-to-cis isomerizations occur concomitantly with a morphological transition from nanoribbons to nanotubes. The nanotube structure persists in water for over six months, stabilized by strong and collective intermolecular interactions. We demonstrate that the nanoribbon-to-nanotube transition is reversible upon heating and that switching between states can be achieved repeatedly. Finally, we use electron microscopy to capture the transition and propose mechanisms for nanoribbon-to-nanotube rearrangement and vice versa. The stability and switchability of photoresponsive AA nanostructures make them viable for a range of future applications.