Multiscale Hierarchical Surface Patterns by Coupling Optical Patterning and Thermal Shrinkage

Abstract

Herein, a simple hierarchical surface patterning method is presented by effectively combining buckling instability and azopolymer-based surface relief grating inscription. In this technique, submicron patterns are achieved using azopolymers, whereas the microscale patterns are fabricated by subsequent thermal shrinkage. The wetting characterization of various topographically patterned surfaces confirms that the method permits tuning of contact angles and choosing between isotropic and anisotropic wetting. Altogether, this method allows efficient fabrication of hierarchical surfaces over several length scales in relatively large areas, overcoming some limitations of fabricating multiscale roughness in lithography and also methods of creating merely random patterns, such as black silicon processing or wet etching of metals. The demonstrated fine-tuning of the surface patterns may be useful in optimizing surface-related material properties, such as wetting and adhesion, producing substrates that are of potential interest in mechanobiology and tissue engineering.

Hierarchical Fourier Surfaces via Broadband Laser Vectorial Interferometry

“…42−44 To address the holographic encoding toward more complex and functional surface textures, different multiplexing techniques, which include multiple or sequential exposures to different light sources and stimuli-combined solutions, have been recently adopted. 11,45,46 Herein, we report on a broadband holographic method that allows single-step inscription of hierarchical Fourier topographies onto the free surface of an azobenzene-based polymer. The approach is based on the interference of two polychromatic beams, i.e., composed of closely spaced wavelengths, originating from a common laser cavity.…”

“…for the design and manufacturing of hierarchically structured platforms. Depending on the target length scale, various technologies based on different processes (mechanical, optical, chemical, thermal, and electrical) – have been developed. Between them, optical processing excels in high-fidelity and spatial resolution as it allows local modifications with a large degree of control over the shape and size of the encoded surface features. , …”

“…To address the holographic encoding toward more complex and functional surface textures, different multiplexing techniques, which include multiple or sequential exposures to different light sources and stimuli-combined solutions, have been recently adopted. ,, …”

In‐situ Monitoring of Photocontrollable Wrinkle Erasure in Azobenzene‐based Supramolecular Systems

“…In this case, the wrinkle evolution of the multi‐layered structure strongly depended on the intermediate photo‐inert layers with wrinkle‐reinforcing or stress relaxation effects. Furthermore, combining buckling instability and all‐optical surface‐patterning of the azopolymer was shown to lead to a controllable hierarchical patterned surface with tuneable adhesion and wetting properties, [22] which opens up opportunities for tissue engineering and biological applications.…”

Efficient Fabrication of Carbon Nanotube‐Based Stretchable Electrodes for Flexible Electronic Devices

“…The shrinking of the elastic substrate could induce the formation of a wrinkled topography. The contraction modes of the elastic substrate include thermal shrinking, [23][24][25] swelling, [26][27][28] pre-stretching, [29][30][31][32][33][34] and so on. Among them, thermal shrinking and swelling can obtain uniform wrinkle structures but with a low shrinkage ratio and poor controllability.…”