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Abstract Health risks affiliated with exposure to a wide variety of toxic gases and vapors are a certainty for first responders such as firefighters and HAZMAT team members but also for countless other professions from water purification and chemical manufacturing to the oil and gas industry, among others, and even the general public. Here the fabrication and testing of several prototypes for a novel toxic gas sensor platform based on ink‐jet printed nematic liquid crystal patterns are described. These sensors require zero power to operate and are characterized by high sensitivity down to highly relevant ppm and ppb levels, fast response times on the order of seconds, improved durability, and an overall design that is highly customizable by the potential end user. The response times of these sensors exponentially decrease with toxic gas concentration, thereby establishing the toxic gas diffusivity dependence of their mode of action. Such prototypes for two particular toxic gases, chlorine, and phosgene, performing interference testing in high humidity and smoke conditions as well as field testing with active firefighters are demonstrated. 

A unique morphology for bent-core liquid crystals forming the B4 phase has been found for a class of tris-biphenyl bent-core liquid crystal molecules with a single chiral side chain in the longer para -side of the molecule. Unlike the parent molecules with two chiral side chains or a chiral side chain in the shorter meta -side, which form helical nano- or microfilament B4 phases, the two derivatives described here form heliconical-layered nanocylinders composed of up to 10 coaxial heliconical layers, which can split or merge, braid, and self-assemble into a variety of modes including feather- or herringbone-type structures, concentric rings, or hollow nest-like superstructures. These multi-level hierarchical self-assembled structures, rivaling muscle fibers, display blue structural color and show immense structural and morphological complexity. 

Abstract Exposure to hazardous chemicals in the air humans breathe voluntarily or during dangerous situations such as fires or military conflicts (i.e., accidental or intentional) is a terrifying certainty. Technical challenges such as low cost, operational simplicity, response time, sensitivity, specificity, and environmental robustness often create barriers to the development of real‐time chemical sensor systems that will be broadly useful to both the private sector and the government. A multi‐mode liquid crystal sensor platform is presented that requires zero power to operate and can, based simply on the device design, be used as acute ppt‐level and analytical ppm‐level (dose × time) sensors. Inkjet printing of nanoparticles with a reactive ligand shell that affects the anchoring of nematic liquid crystal molecules facilitates the creation of sensors devices that produces an unmistakable warning or image solely based on the transmission or reflection of light. Based on the printing resolution and device architecture, these sensor devices can detect multiple gases or vapors on the same device and be used for remote sensing. 

Abstract The range of possible morphologies for bent‐core B4 phase liquid crystals has recently expanded from helical nanofilaments (HNFs) and modulated HNFs to dual modulated HNFs, helical microfilaments, and heliconical‐layered nanocylinders. These new morphologies are observed when one or both aliphatic side chains contain a chiral center. Here, the following questions are addressed: which of these two chiral centers controls the handedness (helicity) and which morphology of the nanofilaments is formed by bent‐core liquid crystals with tris‐biphenyl diester core flanked by two chiral 2‐octyloxy side chains? The combined results reveal that the longer arm of these nonsymmetric bent‐core liquid crystals controls the handedness of the resulting dual modulated HNFs. These derivatives with opposite configuration of the two chiral side chains now feature twice as large dimensions compared to the homochiral derivatives with identical configuration. These results are supported by density functional theory calculations and stochastic dynamic atomistic simulations, which reveal that the relative difference between thepara‐ andmeta‐sides of the described series of compounds drives the variation in morphology. Finally, X‐ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) data also uncover the new morphology for B4 phases featuringp2/msymmetry within the filaments and less pronounced crystalline character.