title: Electrospray formation of gelled nano-aluminum microspheres with superior reactivity.
abstract: Nanometallic fuels with high combustion enthalpy, such as aluminum, have been proposed as a potential fuel replacement for conventional metallic fuel to improve propellant performance in a variety of propulsive systems. Nevertheless, nanometallic fuels suffer from the processing challenges in polymer formulations such as increased viscosity and large agglomeration, which hinder their implementation. In this letter, we employ electrospray as a means to create a gel within a droplet, via a rapid, solvent evaporation-induced aggregation of aluminum nanoparticles, containing a small mass fraction of an energetic binder. The gelled aluminum microspheres were characterized and tested for their burning behavior by rapid wire heating ignition experiments. The gelled aluminum microspheres show enhanced combustion behavior compared to nanoaluminum, which possibly benefits from the nitrocellulose coating and the gelled microstructure, and is far superior to the corresponding dense micrometer-sized aluminum.
authors.affiliation: Department of Chemical and Biomolecular Engineering and Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States.
authors.forename: Haiyang
authors.initials: H
authors.lastname: Wang
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Jian
authors.forename: Shi
authors.initials: S
authors.lastname: Yan
authors.forename: Jeffery B
authors.initials: JB
authors.lastname: DeLisio
authors.forename: Chuan
authors.initials: C
authors.lastname: Huang
authors.forename: Michael R
authors.initials: MR
authors.lastname: Zachariah
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D002623:Chemistry Techniques, Analytical; D003101:Collodion / Q000737:chemistry*; D005782:Gels; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning / Q000379:methods; D008863:Microspheres; D053758:Nanoparticles / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods; D044367:Phase Transition; D011108:Polymers / Q000737:chemistry*; D012997:Solvents; D013696:Temperature
chemical_list: D005782:Gels; D011108:Polymers; D012997:Solvents; D003101:Collodion; D000535:Aluminum