One-step fabrication of hierarchical multiscale surface relief gratings by holographic lithography of azobenzene polymer.

We present one-step method of fabricating hierarchical multiscale grating patterns by using holographic lithography on azobenzene thin films. In this study, we investigate the growth behavior of surface relief gratings in terms of surface morphology change regarding various optical conditions of different fringe visibility, exposure dose and polarization modes of the light interference pattern. The results reveal that different-sized diffractive gratings could be fabricated orthogonally at the same time. We also explain that these orthogonal gratings were developed through the different light-induced deformation mechanism.

Nanoindentation study of optically patterned surface relief grating of azobenzene polymers.

We present the light-controlled hierarchical mechanical properties of optically patterned azobenzene thin films through a nanoindentation study. In this study, we inscribed holographic surface relief grating (SRG) of azopolymers by two-beam coupling-based light interference lithography. The resultant morphological profile of azopolymers was monitored by atomic force microscope (AFM), followed by the nanoindentation study. From the load-displacement curve of the indentation procedure, photomechanical changes of the azopolymers along grating patterns were evaluated in terms of hardness and modulus at the crest and trough of the SRG, respectively. The results revealed that the surface height as well as the mechanical properties was modulated according to the light interference pattern.