Directional Superficial Photofluidization for Deterministic Shaping of Complex 3D Architectures.

The fabrication of micro- and nanostructures is one of the cornerstones of current materials science and technology. There is a strong interest in processing methods capable of manufacturing engineered complex structures on a large area. A method that is gaining a growing attention in this context is based on surface reshaping of photosensitive materials, such as certain azobenzene derivatives by way of a process of light-induced mass migration, also described as "athermal photofluidization". Here, we apply this method to prestructured substrate, converting simple periodic structures initially patterned only in two dimensions into complex-shaped three-dimensional (3D) structures by a single processing step over a large area. The optical variables of the irradiating beam are used to gain unprecedented deterministic control on the resulting 3D architectures. We also provide some initial demonstrations of the potential application of this novel shaping method, including unidirectional wetting surfaces and micro- and nanoscaled fluidic channel manufactured with it.