Fabrication of highly ordered/switchable polymer nanogratings for nano-actuators using nanoimprint lithography.
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.
Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou 215006, People's Republic of China.
Donghai
D
Du
Hongying
H
Wen
Zhijun
Z
Hu
Yuyan
Y
Weng
Weidong
W
Zhang