Design and fabrication of CL-20-based composites with an ordered close-packing structure by inkjet printing

Abstract

Inkjet printing is an additive fabrication technique that utilizes solution-processable materials with the feature of high-precision and micro-scale. However, the fabrication of micro/nano energetic devices with compact structures remains to be a formidable challenge. Here, a simple layer-by-layer induction strategy was reported to fabricate energetic composites with micro/nano and ordered close-packing structures. A printable energetic ink was prepared by one step using 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) as energetic materials, graphene oxide (GO) as a functional filler, and precursor solution as a polymer matrix. By combining inkjet printing with GO induction, the CL-20-based composites obtained in a controllable growth from the printable energetic inks have a porosity of below 10%. Based on the evaporation rate and microdroplet space confinement for crystal growth, a self-assembled interface between the printed layers was constructed by introducing a trace amount of GO flakes and strictly controlling the substrate temperature. The CL-20-based composites with a sub-micro rod-like shape of ~1 µm in diameter and ~10 µm in height were obtained. The elastic modulus of the composites increased by 131% and the detonation speed reached over 8500 m·s−1. The work provides a novel design strategy for the fabrication of micro-energetic devices with high strength and high detonation performance.