Ionic Liquids in Electrospray Propulsion Systems

Prince, Benjamin D.; Fritz, B.; Chiu, Yu‐Hui

doi:10.1021/bk-2012-1117.ch002

Cited by 33 publications

(55 citation statements)

References 37 publications

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“…For pure IL electrosprays, this measurement is typically accomplished through mass spectrometry, and mass spectra for those ILs used in thrusters have been studied extensively. [10][11][12][13][14][15] However, no studies have been conducted to collect the mass composition of a beam from an ILFF electrospray source, which operates using a new fluid and additional field, providing motivation to conduct the research described in this paper.…”

Section: Goal Of Studymentioning

confidence: 99%

“…[10][11][12][13][14][15][19][20][21][22][23][24][25][26] Mass spectrometers can measure the m/q values of the emitted ion and droplet species. As previously stated, understanding the different ion and droplet species within the emitted beam indicate whether the thruster can be used on a high thrust or high I sp mission; some thrusters can operate in variable modes giving them the ability to complete both types of missions.…”

Section: Mass Spectrometry Of Ionic Liquid Electrosprays Cmentioning

confidence: 99%

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Species measurements in the beam of an ionic liquid ferrofluid electrospray source

Terhune¹,

King²,

Hause³

et al. 2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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Anionic liquid ferrofluid (ILFF) using 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-NTf2) as the carrier liquid was emitted from the peak formed via the Rosensweig instability and the electrospray beam was measured using quadrupole and TOF mass spectrometry. The Rosensweig instability peak source (RIPS) was found to operate in three stable emission current modes: transient-emission, lowcurrent, and high-current. Both quadrupole and linear TOF mass spectra for the final two modes were collected, and revealed that the charged-particle species within the electrospray beam varied between the two emission current modes. No correlation between the magnetic field strength and the collected mass spectra was measured. Mass flow measurements using a quartz crystal microbalance revealed that the RIPS only operated at a high mass flow rate of 3-5 ng/s during the startup transient-emission mode and otherwise ran at mass flow rates of 0.03-0.3 ng/s indicating the absence of droplet species during the majority of emission. The RIPS quadrupole mass spectra were compared to a pure ionic liquid needle source quadrupole spectra and it was discovered that multiple species exist in the ILFF electrospray that are attributed to fragments respective ion species, with some species partially comprised of fragments from the polymer used for steric stabilization of the nanoparticles; specifically the block that comprises the stabilization group, poly(N,N-dimethylacrylamide), and the end functionalizing group, CH3CHCOOH. Nomenclature B= magnetic field d = extraction distance E = electric field = gravitational constant = liquid surface tension = magnetic field strength I = electrical current I sp = specific impulse = length of TOF chamber = critical wavelength of the Rosensweig instability = mass = magnetization = power 2 = electrical charge = radius of Taylor cone apex = liquid density = magnetostatic stress = electrostatic stress = surface tension stress = time-of-flight = Thrust = exit velocity = particle velocity = TOF repeller voltage = extractor voltage V = volume

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Section: Goal Of Studymentioning

confidence: 99%

Section: Mass Spectrometry Of Ionic Liquid Electrosprays Cmentioning

confidence: 99%

Species measurements in the beam of an ionic liquid ferrofluid electrospray source

Terhune¹,

King²,

Hause³

et al. 2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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“…One of these candidates, HEHN has also been evaluated by vacuum electrospray for potential use in electrospray thrusters . Typically upon electrospray, (aprotic) ionic liquids produce ions of the form [C (CA) n ] + or [A (CA) n ] − , where C is the cation, A is the anion, and n is the number of ion pairs.…”

Section: Introductionmentioning

confidence: 99%

Dissociation pathways of protic ionic liquid clusters: Alkylammonium nitrates

Patrick

Annesley

2019

J Mass Spectrom

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Protic ionic liquids are promising candidates for many applications, including as spacecraft propellants. For both fundamental interest and understanding clustering and dissociation during electrospray‐based propulsion, it is useful to explore the dissociation pathways of protic ionic liquid clusters, as well as the factors affecting the relative contributions of each pathway to the observed MS/MS spectra. With that said, most of the published reports on ionic liquid cluster dissociation have focused on aprotic ionic liquids. The purpose of the current work is to explore the dissociation pathways (eg, loss of amine, nitric acid, or ion pair) of alkylammonium nitrates using energy‐resolved collision‐induced dissociation. Here, it was found that, in general, protic ionic liquids have multiple dissociation pathways—namely, protic ionic liquids can lose their neutralized cation (here, an alkylamine) or neutralized anion (here, nitric acid)—in addition to the ion pair dissociation familiar to aprotic salt and aprotic ionic liquid clusters. In general, increasing the basicity of the cation (here, through increasing the degree of alkylation) decreases the propensity to follow these alternative pathways. Interestingly, increasing the cluster size has a similar effect: as cluster size increases, nitric acid loss decreases. These results will help better model and design protic ionic liquids for electrospray‐based spacecraft propulsion and help provide a better understanding for the general behavior of protic ionic liquids versus aprotic ionic liquids within mass spectrometers.

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“…1. 18,19 ( ) / I F KQ     (1) These relationships apply to many sprayable liquids including a class used predominately in colloid thrusters called ionic liquids (ILs). ILs are room-temperature liquid salts and are desired because they can be comprised of a multitude of different anion-and-cation combinations which can vary the liquid properties for a given application.…”

Section: Introductionmentioning

confidence: 99%

“…ILs are room-temperature liquid salts and are desired because they can be comprised of a multitude of different anion-and-cation combinations which can vary the liquid properties for a given application. [17][18][19] Beginning in 2013 researchers began using IL ferrofluids (ILFF) as electrospray propellants. 20,21 ILFFs are produced by adding nanometer-scale ferromagnetic particles coated in a surfactant to ILs.…”

Section: Introductionmentioning

confidence: 99%

The effects of magnetic surface stress on electrospray of an ionic liquid ferrofluid

Terhune¹,

King²,

Prince³

et al. 2016

52nd AIAA/SAE/ASEE Joint Propulsion Conference

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Four solutions of an ionic liquid ferrofluid (ILFF) using 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-NTf2) as the carrier liquid were emitted from a capillary electrospray source and its beam was measured using a time-of-flight mass spectrometer (TOF-MS) and a downstream stack of Faraday plates. The solutions had 3.04, 5.98, 8.80, and 14.15 wt% iron-oxide nanoparticles making them susceptible to magnetic fields. A Helmholtz coil was used to impose a magnetic stress onto the electrospray source. The addition of nanoparticles to neat IL increased viscosity, and decreased conductivity and surface tension of the fluid. The emission current followed the proportionality Ĩ Q K 2  = Liquid viscosity P  = Pressure drop through capillary tube = Particle charge Q = Volumetric flowrate min Q = Minimum volumetric flowrate c r = Capillary tube radius ℎ = Time-of-flight u = Particle velocity V = Voltage

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Ionic Liquids in Electrospray Propulsion Systems

Cited by 33 publications

References 37 publications

Species measurements in the beam of an ionic liquid ferrofluid electrospray source

Species measurements in the beam of an ionic liquid ferrofluid electrospray source

Dissociation pathways of protic ionic liquid clusters: Alkylammonium nitrates

The effects of magnetic surface stress on electrospray of an ionic liquid ferrofluid

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