Impact of Stereo- and Regiochemistry on Energetic Materials

The synthesis, physical properties and calculated performances of six stereo- and regioisomeric cyclobutane nitric ester materials is described. While the calculated performances of these isomers, as expected, were similar, their physical properties were found to be extremely different. By altering the stereo- and regiochemistry, complete tunability in the form of low-or high-melting solids, standalone melt-castable explosives, melt-castable explosive eutectic compounds, and liquid propellant materials were obtained. This study demonstrates that theoretical calculations should not be the main factor in driving the design and synthesis of new materials, and that stereo- and regiochemistry offer a new dimension to consider when designing compounds of potential relevance to energetic formulators.<br /

Synthesis and Characterization of Aminopropyltriethoxysilane-Polydopamine Coatings

Polydopamine coatings are of interest due to the fact that they can promote adhesion to a broad range of materials and can enable a variety of applications. However, the polydopamine–substrate interaction is often noncovalent. To broaden the potential applications of polydopamine, we show the incorporation of 3-aminopropyltriethoxysilane (APTES), a traditional coupling agent capable of covalent bonding to a broad range of organic and inorganic surfaces, into polydopamine coatings. High energy X-ray photoelectron spectroscopy (HE-XPS), conventional XPS, near-edge X-ray absorption fine structure (NEXAFS), Fourier transform infrared-attenuated total reflectance (FTIR-ATR), and ellipsometry measurements were used to investigate changes in coating chemistry and thickness, which suggest covalent incorporation of APTES into polydopamine. These coatings can be deposited either in Tris buffer or by using an aqueous APTES solution as a buffer without Tris. APTES–dopamine hydrochloride deposition from solutions with molar ratios between 0:1 and 10:1 allowed us to control the coating composition across a broad range