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π-Stacking is common in materials, but different π−π stacking modes remarkably affect the properties and performances of materials. In particular, weak interactions, π-stacking and hydrogen bonding, often have a great impact on the stability and sensitivity of high-energetic compounds. Therefore, several of energetic materials based on 1,1′-dihydroxyazotetrazole (1) with a nearly flat structure, such as the salts of aminoguanidine (2), 1,3diaminoguanidine (3), imidazole (4), pyrazole ( 5) and triaminoguanidine (6), and a cocrystal of 2-methylimidazole (7), were designed and synthesized. Based on single-crystal diffraction data, thermal decomposition behaviors, and the mechanical sensitivity test, the compounds of 4, 5, and 7 with face-toface π−π stacking display outstanding thermal stability and insensitivity.

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Microfabrication of complex double emulsion droplets with controlled substructures, which resemble biological cells, is an important but a highly challenging subject. Here, a new approach is proposed based on laser‐induced injection of water nanodroplets into a liquid crystal (LC) drop. In contrast to the conventional top‐down microfluidic fabrication, this method employs a series of bottom‐up strategies such as nanodroplet injection, spontaneous and assisted coalescence, elastically driven actuation, and self‐assembly. Each step is controlled precisely by adjusting the laser beam, interfacial tension, and its gradients, surface anchoring, and elasticity of the LC. Whispering gallery mode illumination is used to monitor the injection of droplets. A broad spectrum of double emulsions with a predesigned hierarchical architecture is fabricated and reconfigured by temperature, laser‐induced coalescence, and injection. The proposed bottom‐up method to produce customized microemulsions that are responsive to environmental cues can be used in the development of drug delivery systems, biosensors, and functional soft matter microstructures.

Chiral nematic droplets exhibit abundant topological defect structures, which have been intensively studied, both theoretically and experimentally. However, to observe and reconstruct the exact shape of three-dimensional (3D) defect structures has been a challenging task. In this study, we successfully reconstruct the 3D defect structures within a CLC microsphere with long helical pitches by combining polarized optical microscopy (POM) and laser scanning type fluorescence confocal polarizing microscopy (FCPM). The obtained confocal stack images provide us with the vertical location of disclination defects, to allow reconstruction of the full 3D structures. The reconstructed 3D structures can be viewed from different directions, providing a better understanding of the topological structure. Moreover, the defect lines are identified to be + 1 defects, different from the previous prediction. Thus, FCPM provides an excellent tool to study the complex topological configuration in microspheres, and fosters its potential applicability in new devices based on topologically structured soft media.

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