An extremely superhydrophobic and intrinsically stable Si/fluorocarbon energetic composite based on upright nano/submicron-sized Si wire arrays

Abstract

The extreme superhydrophobicity, together with the chemical inertness of Si element, makes the fabricated Si/fluorocarbon nanostructured energetic composite intrinsically stable.

Si Wire Supported MnO2/Al/Fluorocarbon 3D Core/Shell Nanoenergetic Arrays with Long-Term Storage Stability

“…After being deposited with nominal 120 nm fluorocarbon, Si-W/MnO 2 /Al/fluorocarbon becomes superhydrophobic, as the water drop contact angle of samples with nominal 1 µm and 1.5 µm Al are about 166° and 162°, respectively. According to our previous work 32 , 33 , surface energy of nanoenergetic composites with nano-textures decreases after being coated with fluorocarbon. Besides, with surface texture that has a comparatively high aspect ratio can constitute a superhydrophobic surface as conforming to the Cassie-Baxter model 40 , 41 .…”

“…However, as discussed later, it is enough to get an excellent performance for Si-W/MnO 2 /Al/fluorocarbon energetic composites. Besides, a uniform covering effect is possible to obtain by adjusting related parameters as demonstrated in our previous investigation 33 .…”

“…7 , apart from the main exothermic peak, another smaller exotherm appears on each of the three curves of sample 2 around 320 °C. It presumably originates from the fluorination of the Al/Al 2 O 3 after the low-temperature decomposition of fluorocarbon 30 , 33 . Reports have shown that the pre-ignition reaction observed in various fluoropolymers-containing formulations could intensify the over-all exothermic reaction and combustion process 42 – 45 .…”

“…1 . After a simple and effective deposition of fluorocarbon as well studied in our previous work 30 , 32 , 33 , the ultra-long upright arrays together with the nano-textured surface that benefits from the aluminum particles and beneath porous MnO 2 nanosheets on each array, make the realized energetic composite superhydrophobic, thus ensuring the long-term storage stability.

Figure 1 Schematic illustration of the fabrication process of the 3D silicon wire supported MnO 2 /Al/fluorocarbon nanoenergetic arrays.

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Study on thermal behavior and kinetics of Al/MnO2 poly(vinylidene fluorine) energetic nanocomposite assembled by electrospray

“…Besides, the adding of uoropolymers could bring some other superior properties, for example, anti-humidity and superhydrophobic property. 10,11 Two major uoropolymers have been used widely, Viton uoroelastomer (Viton) 12 and polyvinylidene (PVDF). 13 Due to Viton's poor solubility, it is hard to widely use in nanothermite system even though it has the highest content of uorine in uoropolymers.…”