Phototriggered Mass Migration Consorted with Surface Dewetting in Thin Films of a Liquid Crystalline Azobenzene-containing Dendrimer
Phototriggered Mass Migration Consorted with Surface Dewetting in Thin Films of a Liquid Crystalline Azobenzene-containing Dendrimer
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DOI：
10.1021/ma301170x
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发表时间：
2012-07
期刊：
影响因子：
5.5
通讯作者：
Wen-hui Li;Tomoki Dohi;Mitsuo Hara;Shusaku Nagano;Osamu Haba;K. Yonetake;T. Seki
中科院分区：
文献类型：
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作者：
Wen-hui Li;Tomoki Dohi;Mitsuo Hara;Shusaku Nagano;Osamu Haba;K. Yonetake;T. Seki
合成了一种树枝状聚丙烯亚胺分子，其外围修饰有光敏介晶偶氮苯单元。该化合物在薄膜状态下呈现出高度有序的近晶B或近晶A层结构，其取向平行于基底。当亲水性基底上的90 nm厚的该膜暴露于UV（365 nm）光时，初始的平坦膜形态开始形成孔，随后急剧转变以形成微米级的分离的圆顶结构。在连续紫外光照射下，磁畴高度增加，并达到一个水平的约。8-倍高于初始厚度，这可以与层结构的无序，揭示了掠角入射X射线衍射测量。这种光触发的去湿行为依赖于膜的厚度。较薄的薄膜导致局部迁移，形成更小和更均匀的圆顶。观察到的去湿低于阈值厚度为1…
A dendritic molecule of poly(propylene imine) whose periphery is modified with photoresponsive mesogenic azobenzene units was synthesized. This compound exhibited highly ordered smectic B or smectic A layer structure orienting parallel to the substrate in the film state. When this film of 90 nm thickness on a hydrophilic substrate was exposed to UV (365 nm) light, the initial flat film morphology started to form holes followed by a drastic transformation to form separated dome structure of micrometer levels. Upon continuous UV light irradiation, the domain height increased and reached to a level of ca. 8-fold higher than that of the initial thickness, which can be correlated with the disordering of layer structures as revealed by grazing angle incidence X-ray diffraction measurements. This phototriggered dewetting behavior depended on the film thickness. The thinner film resulted in local migrations to form the smaller and more homogeneous domes. The dewetting was observed below a threshold thickness of 1...