Localization of blue phase liquid crystal with ordered crystallographic direction and well-defined micro-patterning

Abstract

The construction of uniform orientation of crystallographic direction of blue phase is of great importance for its practical applications and the scientific research of multi-dimensional controllable growth of soft matter. With the consideration of the weak thermal stability of blue phase, the uniform lattice orientation of blue phase is combined with localized polymer-stabilization in this work. So the relatively stable fabrication of micro-patterns for blue phase can be realized, and it is promising for researchers to prepare brand new photonic devices. To the best of our knowledge, the relevant reports are rather rare, and the successful implementation of the above ideas is full of difficulties according to current conditions. In this paper, the uniform, patterned and stable orientation of crystallographic direction of blue phase is achieved by using the aforementioned integrated method. Here in this work, facile rubbing alignment is used as the primary way to realize the uniform lattice orientation. Meanwhile, the polymer-stabilization, as an effective technological way, is used to stabilize the frustrated topological structure of aligned blue phase for a better stability and its application perspective. Furthermore, we construct the well-defined micro-patterned blue phase array including one-dimensional and two-dimensional pattern in virtue of facile and effective localized exposure. Simultaneously, the stability of such a micro-pattern under external field is also investigated to evaluate the validity of stabilized superstructure and characteristic behavior of unstable region. As a result, the micro-patterned blue phase array keeps good state even under the adequate exposure to high voltage. Finally, the potential photonic application is explored based on the above micro-patterns which exhibit good optical diffraction effects in the experiment that follows. In conclusion, it really provides a feasible route for achieving stable control about orientation of soft matter, like liquid crystal, and fabricating field-stable and periodic superstructure. Such a research will speed up the development of blue phase liquid crystal in crystallography, electronics, and photonics.