Photochemically Controlled Supramolecular Curdlan/Single-Walled Carbon Nanotube Composite Gel: Preparation of Molecular Distaff by Cyclodextrin Modified Curdlan and Phase Transition Control
Photochemically Controlled Supramolecular Curdlan/Single-Walled Carbon Nanotube Composite Gel: Preparation of Molecular Distaff by Cyclodextrin Modified Curdlan and Phase Transition Control
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DOI：
10.1002/ejoc.201100077
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发表时间：
2011-05-01
影响因子：
2.8
通讯作者：
Harada, Akira
中科院分区：
文献类型：
--
作者：
Tamesue, Shingo;Takashima, Yoshinori;Harada, Akira
我们提出了一种具有分子识别性能的单壁碳纳米管（SWNT）复合材料，它是通过将α-环糊精修饰的可得然胶（CD-CUR）与SWNT在水中混合而制备的。CD-CUR/SWNT复合材料的可见/近红外（维斯/NIR）光谱显示出与金属和半导体碳纳米管的货车霍韦奇异性的带隙跃迁相对应的特征吸收带。用透射电子显微镜（TEM）和原子力显微镜（AFM）对复合材料的结构进行了表征。TEM和AFM图像显示，CD-CUR/SWNT复合材料中纤维直径分布均匀，表明CD-CUR以螺旋状缠绕在SWNT周围形成一维超结构复合材料。由于我们假设CD-CUR/SWNT复合材料具有分子识别性质，因此我们尝试通过使用CD-CUR/SWNT复合材料和具有偶氮苯客体侧基的客体聚合物（pAC（12）Azo）来创建包含SWNT的超分子水凝胶。CD-CUR/SWNT复合物与PAC 12 Azo选择性地形成超分子水凝胶。超分子水凝胶的紫外线照射（λ = 365 nm）降低了反式偶氮基团异构化后的粘度，得到溶胶。相比之下，在λ = 430 nm处用可见光照射（或加热）溶胶状态在2分钟内恢复粘度以恢复水凝胶，表明照射影响相变期间α-CD单元和偶氮苯单元之间的缔合和解离。总之，我们证明了CD-CUR/单壁碳纳米管复合物和光响应溶胶-凝胶超分子单壁碳纳米管水凝胶的形成。
We propose a single-walled carbon nanotube (SWNT) composite with a molecular recognition property, which is prepared by mixing a-cyclodextrin-modified curdlan (CD-CUR) with SWNTs in water. The visible/near-infrared (Vis/NIR) spectrum of the CD-CUR/SWNT composite exhibits characteristic absorption bands corresponding to the band-gap transitions for van Hove singularities of metallic and semiconductor carbon nanotubes. The structure of the CD-CUR/SWNT composites was characterized by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The TEM and AFM images show that the CD-CUR/SWNT composite exhibits dispersed fibers with a narrow fiber diameter distribution, which suggests that CD-CUR helically wraps around SWNTs to form one-dimensional superstructural composites. Because we hypothesized that the CD-CUR/SWNT composite possesses a molecular recognition property, we attempted to create supramolecular hydrogels containing SWNTs by using a CD-CUR/SWNT composite and a guest polymer (pAC(12)Azo) with an azobenzene guest pendant. The CD-CUR/SWNT composite selectively forms supramolecular hydrogels with pAC12Azo. UV irradiation (lambda = 365 nm) of the supramolecular hydrogel decreases the viscosity upon isomerization of the trans-azo group to give the sol. In contrast, irradiation with visible light at lambda = 430 nm (or heating) of the sol state recovers the viscosity to restore the hydrogel within 2 min, indicating that irradiation affects the association and dissociation between the alpha-CD unit and the azobenzene unit during phase transition. In summary, we demonstrate the formation of a CD-CUR/SWNT composite and a photoresponsive sol-gel supramolecular SWNT hydrogel.