Coupling Oscillating–Swirling–Coflowing: A Microfluidic Strategy for Superior Safety and Output Performance of Core–Shell Energetic Microspheres

Abstract

Composite energetic microspheres with core−shell structures have attracted significant attention in solving challenges with low energy and sensitivity. For the superior core−shell and spherical structure, the strategy of coupling oscillating−swirling− coflowing microfluidics with the assistance of spray drying was proposed, which involves model establishment, experimental verification, and performance characterization. The model and verification experiments agreed that the superior core−shell structure and spheroidization can be realized under cocoating and the core−shell ratio of 1:1. Compared with conventional mixtures, the impact sensitivity, friction sensitivity, and burning rate of the sample under optimized conditions significantly improved. It was found that the average burning rate of the propellant added with core−shell energetic microspheres was 5.6% faster than that with the mixture. This study provides critical insights into the design and creation of composite material microspheres with a core−shell structure.

Construction of Ultra-Mixed Energetic Composite Systems by Micro Continuous Flow Coupled with Spray Drying Technology

“…As an essential component for enhancing the interface between oxidizers and reducers, the binder plays a crucial role in composite systems. Achieving sufficient adhesion of the binder in the composite system contributes to the improvement of its mechanical properties . Investigating the composite priority between the adhesive and each component is crucial for describing the microscale assembly process of multicomponent systems.…”

“…Interface binding energy can characterize the degree of difficulty in substance bonding . The magnitude of interface binding energy between different components is not only dependent on the types of substances but also affected by the proportions of each component.…”

“…Achieving sufficient adhesion of the binder in the composite system contributes to the improvement of its mechanical properties. 53 Investigating the composite priority between the adhesive and each component is crucial for describing the microscale assembly process of multicomponent systems. For soluble solutes (KNO 3 , PF), the precipitation order of both solutes during droplet drying is closely related to their concentrations.…”

“…Interface binding energy can characterize the degree of difficulty in substance bonding. 53 The magnitude of interface binding energy between different components is not only dependent on the types of substances but also affected by the proportions of each component. In order to optimize the modeling of multicomponent microscale assembly processes, the interaction energy relationship between the adhesive and each component was analyzed using Materials Studio 2020.…”

Fabrication of polymeric microspheres for biomedical applications

“…Generally, microfluidic methods for producing single emulsions contain two immiscible liquid phases (the dispersed phase and the continuous phase) through injection from a precisely designed microchannel, followed by the droplets being sheared off at the junction where the immiscible phases meet. 59,60 Based on the variance of the device structures, multiple emulsions manipulated by microfluidics technology can function as templates for preparing microspheres with complex structures, such as core-shell microspheres, 61 multi-core microcapsules. 62 During this process, well-connected microchannels with two different geometries and opposite wettability were employed to produce double emulsions by the formation of an internal droplet in the first geometry and the external droplet in the second.…”