期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2015
卷号：112
期号：50
页码：15291-15296
DOI：10.1073/pnas.1513348112
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceIt has been challenging to directly probe the molecular-scale organization of nonglassy nematic liquid crystal (LC) molecules without altering the LC directors. Here, we design and synthesize a new type of stable nematic liquid crystal monomer (LCM) system with strong dipole-dipole interactions. The new LCMs can achieve faithful anchoring and alignment control at various boundaries, analogous to that of small molecule LCs. Upon photo-cross-linking, the orientational order of mesogens is effectively and faithfully locked, allowing for direct visualization of the LC director field and defect structures by scanning electron microscopy (SEM) with 100-nm resolution. Further, we use SEM imaging to calculate the extrapolation length of the LCM for planar and homeotropic anchoring. Liquid crystals (LCs), owing to their anisotropy in molecular ordering, are of wide interest in both the display industry and soft matter as a route to more sophisticated optical objects, to direct phase separation, and to facilitate colloidal assemblies. However, it remains challenging to directly probe the molecular-scale organization of nonglassy nematic LC molecules without altering the LC directors. We design and synthesize a new type of nematic liquid crystal monomer (LCM) system with strong dipole-dipole interactions, resulting in a stable nematic phase and strong homeotropic anchoring on silica surfaces. Upon photopolymerization, the director field can be faithfully "locked," allowing for direct visualization of the LC director field and defect structures by scanning electron microscopy (SEM) in real space with 100-nm resolution. Using this technique, we study the nematic textures in more complex LC/colloidal systems and calculate the extrapolation length of the LCM.
