Du Donghai, Wen Hongying, Hu Zhijun, Weng Yuyan, Zhang Weidong
Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou 215006, People's Republic of China.
Nanotechnology. 2014 May 16;25(19):195503. doi: 10.1088/0957-4484/25/19/195503. Epub 2014 Apr 24.
Polymer micro/nano-actuators are attracting tremendous interest due to their potential applications in micro/nano-mechanical systems and lab-on-a-chip systems. To achieve this, thin films of stimuli-responsive polymers are required to be patterned at the micro/nanometer scale, and also to possess highly ordered orientation in the responsive component. We demonstrate here that nanoscale patterning and uniaxial alignment of liquid crystalline mesogens can be simultaneously achieved by nanoimprint lithography performed in the liquid crystalline mesophase. Photoactive azobenzene mesogens were aligned parallel to the nanogratings imprinted in the films. The degree of alignment depended on the extent of nanoconfinement. The nanogratings expanded in the direction perpendicular to the film upon exposure to uniform UV irradiation, because of trans-to-cis isomerization. In addition, the reversible deformation amplitude strongly depended on the degree of alignment of the photoactive azobenzene mesogens.
聚合物微纳致动器因其在微纳机械系统和芯片实验室系统中的潜在应用而备受关注。要实现这一点，需要将刺激响应性聚合物薄膜在微纳尺度上进行图案化，并且在响应组件中具有高度有序的取向。我们在此证明，通过在液晶中间相进行的纳米压印光刻，可以同时实现液晶基元的纳米级图案化和单轴排列。光活性偶氮苯液晶基元与薄膜中印刻的纳米光栅平行排列。排列程度取决于纳米限域的程度。由于反式到顺式异构化，纳米光栅在均匀紫外光照射下会在垂直于薄膜的方向上膨胀。此外，可逆变形幅度强烈依赖于光活性偶氮苯液晶基元的排列程度。
