Panoscopic organization of anisotropic colloidal structures from photofunctional inorganic nanosheet liquid crystals.
Panoscopic organization of anisotropic colloidal structures from photofunctional inorganic nanosheet liquid crystals.
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DOI：
10.1039/c3cp54140a
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发表时间：
2014-01
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影响因子：
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通讯作者：
T. Nakato;Yoshihiro Nono;E. Mouri;M. Nakata
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文献类型：
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作者：
T. Nakato;Yoshihiro Nono;E. Mouri;M. Nakata
将通过层状晶体的剥离制备的厚度为约1 nm且横向尺寸为几微米的无机纳米片的胶体液晶转化为分级组织的阵列，其结构通过称为类晶的液晶域作为二级结构单元的生长从纳米到宏观长度尺度进行控制，然后受控地施加外部场。通过在室温下孵育液晶来实现类晶的生长。的tactoids，然后组装成高阶结构的特征长度的子毫米到毫米的同时施加的交流电场和重力，其方向确定的阵列的最终纹理图案。当在相同方向上施加电场和重力时观察到网状织构，而当在垂直于重力的方向上施加电场时观察到纳米片单向排列的条纹织构。利用发育良好的类晶是宏观结构控制的关键。由于纳米片具有宽带隙半导体性质，纳米片条纹阵列表现出反射纳米片相对于入射光的偏振方向的对准的反射。
Colloidal liquid crystals of inorganic nanosheets with thickness of around 1 nm and lateral dimensions of several micrometers prepared by exfoliation of a layered niobate are converted to hierarchically organized arrays whose structures are controlled from the nano to macroscopic length scale through the growth of liquid crystalline domains called tactoids as the secondary building blocks followed by controlled application of external fields. Growth of the tactoids is attained by incubation of the liquid crystals at room temperature. The tactoids are then assembled into higher-order structures with characteristic lengths of sub-mm to mm under the simultaneous application of an ac electric field and gravity, whose directions determine the final textural motif of the arrays. Whereas a net-like texture is observed when applying the electric and gravitational forces in the same direction, a striped texture where the nanosheets are unidirectionally aligned is observed when the electric field is applied in the direction perpendicular to gravity. The use of well-grown tactoids is key to the macroscopic structural control. Since the niobate nanosheets have wide band-gap semiconducting nature, the nanosheet stripe arrays exhibit photocatalysis that reflected the alignment of the nanosheets with respect to the polarized direction of impinging light.