Three cocrystals of ammonium perchlorate (AP) with a series of crown ethers have been prepared successfully through the solvent/antisolvent method, including 18-crown-6 (18C6), benzo-18-crown-6 (B18C6), and dibenzo-18-crown-6 (DB18C6). Crystal structures of the three cocrystals characterized by single crystal X-ray diffraction (SXD) reveal that all the cocrystals belong to the monoclinic system, in which the space group of the 1 : 1 cocrystal of AP/18C6 and AP/B18C6 is P2 1 /n, P2 1 /c for the 1 : 1.5 cocrystal of AP/DB18C6. The main intermolecular interactions in the three cocrystals are hydrogen bonds and π-π stacking. Powder X-ray diffraction (PXRD) analyses have been performed to scrutinize the purity of all the crystals. The water contact angles of the three cocrystals were measured to be 23.3°(AP/18C6), 25.4°( AP/B18C6), and 75.4°(AP/DB18C6), increasing with the number of phenyl groups connected to the crown ether, and the surface energy of the three cocrystals are greatly decreased compared to AP. The thermal properties of the cocrystals were investigated by thermogravimetry-differential scanning calorimetry (TG-DSC) and hot-stage optical microscopy (HSOM). The results indicate that the decomposition peak temperatures of the three cocrystals are greatly decreased compared to that of pure AP. In particular, the heat release increases from 475.5 J g −1 of AP to 1304.2 J g −1 for AP/B18C6 and 1488.4 J g −1 for AP/ DB18C6. So, through carefully choosing the co-former of AP, cocrystallization can comprehensively tune the hygroscopicity and the thermal decomposition property of AP.

A facile and mild method, liquid‐liquid interface crystallization (LLIC), is reported for the fabrication of the hierarchical structure of octahydro‐1,3,5‐tetranitro‐1,3,5,7‐tetrazocine (HMX) under ambient conditions. The morphology and structure are characterized by field emission scanning electron microscopy (FE‐SEM), dynamic light scattering (DLS), powder X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy. A three‐dimensional hierarchical dandelion‐like HMX architecture is obtained through self‐assembling of the submicron particles with a main diameter range of 250–700nm at the interface of DMSO solution and CH2Cl2. Except the main polymorph β, the δ phase is found in the product. Thermal analyses are performed, and the kinetic parameter is calculated. The results indicate that hierarchical structure HMX presents much higher activation energy (280.82 KJ mol−1) than raw HMX (258.90 KJ mol−1). Similarly, the exothermic decomposition peak of HMX hierarchical structure also reaches 287.7 °C and is basically the same as raw HMX (288.4 °C). From the results of the sensitivity tests, the impact and friction sensitivities of HMX are significantly increased compared with those of raw HMX. In this work, the successful application of LLIC to energetic materials is demonstrated, thereby providing a potential method for the preparation of hierarchical structure of high‐energy ammonium nitrate explosives.