Dr. Wei Hu
Dr. Wei Hu
Nanjing University, China
Title: Ordered liquid crystal hierarchical superstructures enabled by photoalignment
Mesoscopic hierarchical superstructures bridge the micro and macro worlds, and provide insights for the development of new functional materials. Much effort has been devoted to mimic the hierarchical organization observed in nature, however, the precise realization and rational control of ideal large-area hierarchical superstructures remains challenging. Liquid crystals (LCs) are excellent building blocks due to their extra field controllable self-assembly behavior and resultant physical property. Among them, cholesteric liquid crystal, smectic liquid crystal and blue phase liquid crystal which are featured by periodic helices, ordered lamellar structures and cubically arranged double-twist cylinders have drawn intensive attention. Here, a LC photopatterning technique [1,2] which enables the accurate, arbitrary and reconfigurable azimuthal angle control of LCs is introduced to manipulate the LC hierarchical superstructures. By this means, the in-plane helical axes of cholesteric liquid crystals [3,4], the spacial smectic layer curvation of SmA phase [5] and the crystallographic directions of blue phase [6] are rationally designed and arbitrarily controlled over centimeter scales. The growth of unique fingerprint textures including spiral and wave-like continuous gratings are demonstrated. Such CLC superstructures could also be obtained in semi-free films. The dopant of an azobenzene chiral molecular switch further supplies great flexibility to realize a continuous grating rotation under photo stimuli. Freely tailoring of the geometry and clustering characteristics of focal conic domains of smectic A has been realized, which have great potentials in polarization imaging. Patterned crystallographic orientation of cubic blue phase soft lattice is demonstrated and several advanced reflective photonic applications have been presented. This study broadens the fundamental understanding of self-assembled soft materials and enhances the construction of desired hierarchical superstructures. It will bring new opportunities to the design of novel advanced photonic devices.

Figure. Ordered liquid crystal hierarchical superstructures formed by photoaligned cholesteric liquid crystals, smectic liquid crystal and blue phase liquid crystal


1. H. Wu, W. Hu,* H. Hu, et al. Opt. Express 2012, 20, 16684. 

2. B. Wei, W. Hu,* Y. Ming, et al. Adv. Mater. 2014, 26, 1590. 

3. L. Ma, S. Li, W. Hu*, et al. Adv. Optical Mater. 2015, 3, 1691. 

4. L. Ma, W. Duan, W. Hu*, et al. Polymers 2017, 9, 295. 

5. L. Ma, M. Tang, W. Hu,* et al. Adv. Mater. 2017, 29, 1606671. 

6. Z. Zheng#, C. Yuan#, W. Hu#, et al. Adv. Mater. 2017, 1703165.

Wei Hu earned his Ph.D. in 2009 from College of Chemistry, Jilin University. Then he joined the College of Engineering and Applied Sciences, Nanjing University and became a faculty. He is now an associate professor of materials with research interest focusing on liquid crystal (LC) materials and devices, especially on self-assembled LC superstructures, the application of LC photoalignment in optical field control, liquid crystal telecom and THz devices. Dr. Hu has published 87 journal papers, 5 book chapters, over 60 conference contributions and held 46 issued/pending patents. His initiative works in hierarchical LC superstructure architecture, optically addressed spatial light modulating and specific optical field control from Vis to THz have received intensive attention in the materials, physics and optics communities. He is now a member of the Society for Information Display (SID), Chinese Chemical Society (CCS), Chinese Physical Society (CPS), Jiangsu Optical Society and Jiangsu Mass entrepreneurship, innovation. Dr. Hu serves as an Editorial Board Member for Scientific Reports and an active reviewer for over 20 journals. He was elected by the Editorial Board of Liquid Crystals as one of the 30 distinguished early career researchers on liquid crystals in the world (2016), and wins the Cyrus Tang Young Scientist Award (2017).