Gao, MinMinGaoKim, Young-KiYoung-KiKimZhang, CuiyuCuiyuZhangBorshch, VolodymyrVolodymyrBorshchZhou, ShuangShuangZhouPark, Heung-ShikHeung-ShikParkJákli, AntalAntalJákliLavrentovich, Oleg DOleg DLavrentovichTamba, Maria-GabrielaMaria-GabrielaTambaKohlmeier, AlexandraAlexandraKohlmeierMehl, Georg HGeorg HMehlWeissflog, WolfgangWolfgangWeissflogStuder, Daniel FranzDaniel FranzStuderZuber, BenoîtBenoîtZuber0000-0001-7725-5579Gnägi, HelmutHelmutGnägiLin, FangFangLin2024-10-232024-10-232014-10https://boris-portal.unibe.ch/handle/20.500.12422/126616Liquid crystals (LCs) represent a challenging group of materials for direct transmission electron microscopy (TEM) studies due to the complications in specimen preparation and the severe radiation damage. In this paper, we summarize a series of specimen preparation methods, including thin film and cryo-sectioning approaches, as a comprehensive toolset enabling high-resolution direct cryo-TEM observation of a broad range of LCs. We also present comparative analysis using cryo-TEM and replica freeze-fracture TEM on both thermotropic and lyotropic LCs. In addition to the revisits of previous practices, some new concepts are introduced, e.g., suspended thermotropic LC thin films, combined high-pressure freezing and cryo-sectioning of lyotropic LCs, and the complementary applications of direct TEM and indirect replica TEM techniques. The significance of subnanometer resolution cryo-TEM observation is demonstrated in a few important issues in LC studies, including providing direct evidences for the existence of nanoscale smectic domains in nematic bent-core thermotropic LCs, comprehensive understanding of the twist-bend nematic phase, and probing the packing of columnar aggregates in lyotropic chromonic LCs. Direct TEM observation opens ways to a variety of TEM techniques, suggesting that TEM (replica, cryo, and in situ techniques), in general, may be a promising part of the solution to the lack of effective structural probe at the molecular scale in LC studies. Microsc. Res. Tech. 77:754-772, 2014. © 2014 Wiley Periodicals, Inc.enfreeze fracturehigh-pressure freezingCEMOVISthermotropiclyotropic600 - Technology::610 - Medicine & healtharticle10.7892/boris.588592504504510.1002/jemt.22397