Phase transitions of 8CB liquid crystal visualized using in situ liquid-phase transmission electron microscopy

This data collection presents videos of phase transitions: smectic A-nematic (SmA-N) and nematic-isotropic (N-I) of 4′-Octyl-4-cyanobiphenyl (8CB) liquid crystal recorded using liquid-phase scanning transmission electron microscopy (LP-STEM). The videos are made from fast-series frames acquired at a resolution of 2048x2048, a frame time of 0.84s, and a dwell time of 200ns. In the experiment, we used low-magnification STEM mode in the Talos F200i transmission electron microscope (Thermofisher Scientific), operating at an accelerating voltage of 200 kV and a camera length of 4.6m. For each video, the maximum magnification was 3370x. The individual image series were recorded at a resolution of 2048x2048, but to reduce the file size, the video resolution was lowered to 1024x1024. At the maximum magnification of 3370x, the pixel size at reduced resolution is equal to 29 nm. The detailed metadata of each data set is provided in text files.Videos 1-3 show sequences of phase changes SmA-N and N-I, and accompanying defect formation in the nematic phase, at varying electron dose rates of: 0.79 e-/nm2s (video-1), 1.49 e-/nm2s (video-2), and 2.72 e-/nm2s (video-3). FPS value for videos 1-3 is 10. Video-3 is divided into four parts: Video-3-part-I, Video-3-part-II, Video-3-part-III, and Video-3-part-IV. Video-4 shows a similar sequence of SmA-N and N-I phase transitions at an electron dose rate of 2.79 e-/nm2s, with visible surface tension effects during the N-I phase change. FFPS value for video-4 is 10. Video-5 was recorded with an additional heat source (laser) turned on and off a few times to induce the N-I transition and show the process's reversibility. FPS value for video-5 is 25.