Multifunctional Fluorine-Rich Ion-Conductive Elastomer for Combustion-Enhanced Energetic Composites

Abstract

Achieving a balanced combination of ultra-stretchability, electrostatic safety, self-healing capability, and enhanced combustion performance in polymer-bonded explosives (PBXs) remains a critical challenge. Herein, we report a series of fluorine-rich ion-conductive elastomers (ICEs) derived from a polymerizable deep eutectic solvent (PDES) composed of 2,2,3,4,4,4-hexafluorobutyl acrylate (HFBA) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The formation mechanism of the PDES(HFBA2-LiTFSI) system was elucidated via FT-IR spectroscopy, revealing that the carbonyl groups of HFBA participate in Li+ solvation, and a homogeneous PDES is formed at an HFBA:LiTFSI molar ratio of 2:1. Three elastomer systems, namely LiF2CNo, LiF2CPEGDA and LiF2CVFSoil were systematically investigated. By introducing a fluorosiloxane crosslinker (VFSoil), the resulting LiF2CVFSoil exhibited the most favorable comprehensive performance with toughness of 23.23±0.05 MJ·m–3, ionic conductivity of 7.517×10–5 S/m, thermally activated self-healing capability, and favorable hydrophobicity. When applied as a binder for cyclotetramethylenetetranitramine (HMX, octogen)-based composites, the H50(LiF2CVFSoil)50 formulation maintained excellent stretchability with an elongation at break of 578.12% and exhibited thermally activated self-healing capability at 80 °C. Furthermore, the H90(LiF2CVFSoil)10 formulation improved both the mechanical and electrostatic safety relative to pristine HMX. Moreover, high-speed photography and infrared thermography revealed that the fluorine-rich binder LiF2CVFSoil effectively disrupted the alumina passivation shell, suppressed aluminum nanoparticles (nano-Al) agglomeration, and delivered superior combustion uniformity and sustained high flame temperatures in aluminized formulations. This work presents a promising molecular design platform for developing next-generation PBXs featuring ultra-stretchability, thermally activated self-healing capability, and enhanced combustion performance.