An achiral, bent-core mesogen forms several tilted smectic liquid crystal phases, including a non-polar, achiral de Vries smectic A which transitions to a chiral, ferroelectric state in applied electric fields above a threshold. At lower temperature, a chiral, ferrielectric phase with a periodic, supermolecular modulation of the tilt azimuth, indicated by a Bragg peak in carbon-edge resonant soft X-ray scattering, is observed. The absence of a corresponding resonant Umklapp peak identifies the superlayer structure as a twist-bend-like helix that is only weakly modulated by the smectic layering.

We demonstrate a method for training a convolutional neural network with simulated images for usage on real-world experimental data. Modern machine learning methods require large, robust training data sets to generate accurate predictions. Generating these large training sets requires a significant up-front time investment that is often impractical for small-scale applications. Here we demonstrate a 'full-stack' computational solution, where the training data set is generated on-the-fly using a noise injection process to produce simulated data characteristic of the experimental system.We demonstrate the power of this full-stack approach by applying it to the study of topological defect annihilation in systems of liquid crystal freely-suspended films. This specific experimental system requires accurate observations of both the spatial distribution of the defects and the total number of defects, making it an ideal system for testing the robustness of the trained network. The fully trained network was found to be comparable in accuracy to human hand-annotation, with four-orders of magnitude improvement in time efficiency. arXiv:1908.05271v1 [cond-mat.soft]

A technique of mechanical airflow sensing based on coupling to a film of fluid smectic liquid crystals is presented. A gas jet confined to a narrow channel induces flow in a continuous, freely suspended film with racetrack geometry, whose velocity field is then mapped using video microscopy and particle tracking techniques. Because the nanofilm has so little mass compared to the air, its velocity provides a direct readout of the velocity profile of the gas in the channel. This method of flow measurement offers several advantages over conventional mechanical flow meters: It has linear sensitivity, and so, it can operate at low flows, and the energy lost due to the measurement is negligible.

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