From Event: SPIE Organic Photonics + Electronics, 2016
The helical nanofilament (HNF) liquid crystal (LC) phase of bent core mesogens (also commonly termed the B4 phase) is among the most unique and exotic LC phases known. The structure involves a spontaneous hierarchical self assembly of molecules leading to a supramolecular twisted rod structure with a square cross section approximately 30 nm on a side, with the length of the filaments unconstrained.
Based upon solid state NMR data, we have proposed that the helical nanofilaments actually represents an unusual assembly of organic crystalline nanoparticles, which form an LC phase, in the case of NOBOW existing in the temperature range between about 150°C and 110°C, which becomes a glass at temperatures below 110°C. That is, the HMF phase is not a typical molecular LC, but an LC of nanocrystals.
Descriptions of the structure of these nanoparticles, their LC phases, and approaches to alignment will be given. Also, the fascinating and potentially useful behavior of the HNF phase as a host for other materials (LC and non-LC) in nanostructured composites will be presented.
David Walba, Chenhui Zhu, Alexander Hexemer, Dong Ki Yoon, Hanim Kim, Eva D. Korblova, Dong Chen, Michael Tuchband, and Noel Clark, "Host-guest chemistry in the helical nanofilament phase
(Conference Presentation)," Proc. SPIE 9940, Liquid Crystals XX, 99400Y (Presented at SPIE Organic Photonics + Electronics: August 29, 2016; Published: 3 November 2016); https://doi.org/10.1117/12.2236100.5167077742001.
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Study of self-shadowing effect as a simple means to realize nanostructured thin films and layers with special attentions to birefringent obliquely deposited thin films and photo-luminescent porous silicon