Carbon Nanostructures Derived through Hypergolic Reaction of Conductive Polymers with Fuming Nitric Acid at Ambient Conditions

Abstract

Hypergolic systems rely on organic fuel and a powerful oxidizer that spontaneously ignites upon contact without any external ignition source. Although their main utilization pertains to rocket fuels and propellants, it is only recently that hypergolics has been established from our group as a new general method for the synthesis of different morphologies of carbon nanostructures depending on the hypergolic pair (organic fuel-oxidizer). In search of new pairs, the hypergolic mixture described here contains polyaniline as the organic source of carbon and fuming nitric acid as strong oxidizer. Specifically, the two reagents react rapidly and spontaneously upon contact at ambient conditions to afford carbon nanosheets. Further liquid-phase exfoliation of the nanosheets in dimethylformamide results in dispersed single layers exhibiting strong Tyndall effect. The method can be extended to other conductive polymers, such as polythiophene and polypyrrole, leading to the formation of different type carbon nanostructures (e.g., photolumincent carbon dots). Apart from being a new synthesis pathway towards carbon nanomaterials and a new type of reaction for conductive polymers, the present hypergolic pairs also provide a novel set of rocket bipropellants based on conductive polymers.

Structure/Properties Relationship of Anionically Synthesized Diblock Copolymers “Grafted to” Chemically Modified Graphene

“…The hydrophobic two-dimensional (2-D) sp 2 carbon nanostructures are susceptible to covalent or non-covalent surface chemical modification, inducing functional groups able to react with polymeric chains [ 1 , 5 ]. Grafting polymers on modified graphene sheets results in nanocomposites presenting a combination of properties resulting from both materials, namely improved solubility and interfacial energy alternations [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. The reaction between polymers and graphene oxide nanosheets involves two methods and specifically the “ grafting from ” [ 17 ], where the GO–initiator complex is primarily prepared in order to initiate the polymerization from the GO surface, and the “ grafting to ” [ 18 ], where the polymeric precursor bearing a functional group reacts with the chemically modified GO [ 19 , 20 , 21 , 22 , 23 ].…”

Hypergolic Ignition of 1,3-Cyclodienes by Fuming Nitric Acid toward the Fast and Spontaneous Formation of Carbon Nanosheets at Ambient Conditions

“…The produced foam is considered an excellent absorbent material for oil removal, as well as a suitable thermal insulator and flame retardant. It is interesting to note that poly(1,3-cyclohexadiene), which has been synthesized via anionic polymerization method under high vacuum techniques [27][28][29][30][31], also reacts hypergolically with fuming nitric acid (Figure 11), thus expanding the usage of the method beyond monomers' reactivity [16]. It is interesting to note that poly(1,3-cyclohexadiene), which has been synthesized via anionic polymerization method under high vacuum techniques [27][28][29][30][31], also reacts hypergolically with fuming nitric acid (Figure 11), thus expanding the usage of the method beyond monomers' reactivity [16].…”

“…In hypergolics, a fuel and an oxidizer ignite spontaneously upon contact without external stimuli. Although the concept is widely used in space flights and the rocket industry for several decades now [5][6][7][8], it is only recently that their role in carbon materials synthesis has been explored by our group [9][10][11][12][13][14][15][16].…”

“…More specifically, carbon nanosheets had been previously obtained from self-ignition of lithium dialkylamides in air [9], highly crystalline graphite through the spontaneous Micro 2021, 1 reaction of the acetylene-chlorine hypergolic mixture [10], carbon dots or nanosheets via hypergolic pairs based on Girard's reagent T or nitrile rubber and fuming nitric acid as strong oxidizer [11], carbon nanosheets or hydroxylated fullerenes using coffee grains or C 60 as carbon sources and sodium peroxide as strong oxidizer [12], dense or hollow spheres derived from the reaction of ferrocene with liquid bromine at room temperature [13], carbon nanodiscs obtained through the cyclopentadienyllithium-fuming nitric acid hypergolic pair [14], carbon nanosheets via the hypergolic reaction of furfuryl alcohol with fuming nitric acid at ambient conditions [15], and lastly, carbon nanosheets or carbon dots from the hypergolic ignition of conductive polymers [16]. The new synthesis method not only allows the fast and spontaneous formation of the above-mentioned nanocarbons at ambient conditions but also produces useful energy in the process, such as chemical, mechanical, thermoelectric, photovoltaic, or heating fluids.…”

Hypergolic Synthesis of Inorganic Materials by the Reaction of Metallocene Dichlorides With Fuming Nitric Acid At Ambient Conditions: The Case of Photocatalytic Titania

“…Recently our group has introduced hypergolic materials synthesis as a radically new preparative method in materials science [4][5][6][7][8][9][10][11][12]. At the heart of this new technique are hypergolic reactions.…”