DNA is a common biomaterial in nature as well as a good building block for producing useful structures, due to its fine feature size and liquid crystalline phase. Here, we demonstrate that a combination of shear-induced flow and microposts can be used to create various kinds of interesting microstructure DNA arrays. Our facile method provides a platform for forming multi-scale hierarchical orientations of soft- and biomaterials, using a process of simple shearing and controlled evaporation on a patterned substrate. This approach enables potential patterning applications using DNA or other anisotropic biomaterials based on their unique structural characteristics.

Topological defects in liquid crystal (LC) phases have been considered critical from the areas in topology and self‐assembly, as well as in applications such as optical vortex generation, particle manipulation system, and template for material micropatterning. An approach for generating and modulating various patterns of LC defects is presented in a single cell by varying the electrode configurations. Periodic LC defect arrays including −1 topological defect in the nematic phase can be achieved by simply adjusting crossed electrodes. Specifically, the fourfold symmetric −1 defect pattern is used as a vortex beam generator and a particle trapping agent with control either of the frequency of the applied electric field or the temperature. The approach suggested here would be beneficial to extend the use of LC patterns in lithographic tools and optoelectronic devices.

The arrangement of mesogenic units determines mechanical response of the liquid crystal polymer network (LCN) film to heat. Here, we show an interesting approach to programming three-dimensional patterns of the LCN films with periodic topological defects generated by applying an electric field. The mechanical properties of three representative patterned LCN films were investigated in terms of the arrangement of mesogenic units through tensile testing. Remarkably, it was determined that LCN films showed enhanced toughness and ductility as defects increased in a given area, which is related to the elastic modulus mismatch that mitigates crack propagation. Our platform can also be used to modulate the frictional force of the patterned LCN films by varying the temperature, which can provide insight into the multiplex mechanical properties of LCN films.

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