Search NASA⌕ Search

SEARCH · Search NASA

Results for “Quaternary ammonium”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Phosphate anion-quaternary ammonium ion pair coordinated polymer membranes

Ion exchange membranes materials according to the present disclosure exhibit improved conductivity at low and intermediate relative humidity without sacrificing mechanical strength. Polymers are provided that include a backbone with one or more aryl groups, a halocarbyl group, and a halocarbyl side chain attached to the backbone, wherein the halocarbyl side chain includes a halide separated from the backbone by a hydrocarbyl chain, a hydrocarbyl ring, or combinations thereof. The halide is substituted with a tertiary amine and halide anions are then exchanged with hydroxide anions. The polymers are then contacted with phosphoric acid, which is deprotonated by the hydroxide ions, forming anions which enhance interactions with adjacent quaternary ammonium groups and induce excess phosphoric acid molecules to cluster around those quaternary ammonium groups. The membranes exhibit negligible dopant leaching even at high relative humidity.

Bae, Chulsung↗
DOE OSTI2025

H 2 O and CO 2 Sorption in Ion-Exchange Sorbents: Distinct Interactions in Amine Versus Quaternary Ammonium Materials

This article examines how water (H₂O) and carbon dioxide (CO₂) interact with two classes of ion-exchange sorbents — a primary amine sorbent and a quaternary ammonium (QA⁺) sorbent — using calorimetry, thermal gravimetric analysis, gas analysis, and molecular modeling. Here, the QA⁺ sorbent exhibits stronger binding to both H₂O and CO₂ but also shows thermal stability limitations. Mixed-gas experiments reveal that humidity strongly influences CO₂ uptake and that moisture-driven sorbent regeneration enables cyclic moisture swing CO₂ capture, with implications for low-energy CO₂ separation from dilute gas streams.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Few‐Unit‐Cell MFI Zeolite Synthesized using a Simple Di‐quaternary Ammonium Structure‐Directing Agent

Abstract Synthesis of a pentasil‐type zeolite with ultra‐small few‐unit‐cell crystalline domains, which we call FDP (few‐unit‐cell crystalline domain pentasil), is reported. FDP is made using bis‐1,5(tributyl ammonium) pentamethylene cations as structure directing agent (SDA). This di‐quaternary ammonium SDA combines butyl ammonium, in place of the one commonly used for MFI synthesis, propyl ammonium, and a five‐carbon nitrogen‐connecting chain, in place of the six‐carbon connecting chain SDAs that are known to fit well within the MFI pores. X‐ray diffraction analysis and electron microscopy imaging of FDP indicate ca. 10 nm crystalline domains organized in hierarchical micro‐/meso‐porous aggregates exhibiting mesoscopic order with an aggregate particle size up to ca. 5 μm. Al and Sn can be incorporated into the FDP zeolite framework to produce active and selective methanol‐to‐hydrocarbon and glucose isomerization catalysts, respectively.

Lu, Peng↗
DOE OSTI2021

Few‐Unit‐Cell MFI Zeolite Synthesized using a Simple Di‐quaternary Ammonium Structure‐Directing Agent

Abstract Synthesis of a pentasil‐type zeolite with ultra‐small few‐unit‐cell crystalline domains, which we call FDP (few‐unit‐cell crystalline domain pentasil), is reported. FDP is made using bis‐1,5(tributyl ammonium) pentamethylene cations as structure directing agent (SDA). This di‐quaternary ammonium SDA combines butyl ammonium, in place of the one commonly used for MFI synthesis, propyl ammonium, and a five‐carbon nitrogen‐connecting chain, in place of the six‐carbon connecting chain SDAs that are known to fit well within the MFI pores. X‐ray diffraction analysis and electron microscopy imaging of FDP indicate ca. 10 nm crystalline domains organized in hierarchical micro‐/meso‐porous aggregates exhibiting mesoscopic order with an aggregate particle size up to ca. 5 μm. Al and Sn can be incorporated into the FDP zeolite framework to produce active and selective methanol‐to‐hydrocarbon and glucose isomerization catalysts, respectively.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Investigating Silver Nanoparticle Interactions with Quaternary Ammonium Functionalized Triblock Copolymers and Their Effect on Midblock Crystallinity

Interactions between silver nanoparticles and a cationic triblock copolymer significantly alter bulk material properties and can be tuned by functionalizing the polymer with different quaternary ammonium cations (QACs). In this work, poly-chloromethylstyrene-b-polycyclooctene-b-polychloromethylstyrene (PCMS-b-PCOE-b-PCMS) was quaternized with either methylpiperidinium (MPRD) or trimethylammonium (TMA). The surface interacting groups were identified using FT-IR to be the phenyl rings, the QACs from the outer blocks, and vinyl groups from the PCOE midblock. Changes in thermal characteristics and crystallinity were highly dependent on the QAC, uncovering differences in the nature of the interactions between silver and TMA or MPRD. Interactions induced by TMA greatly hinder crystalline domain formation and give rise to a higher water content, while MPRD promotes certain crystalline orientations and provides a greater degree of crystallinity with a lower water content. In this work, our findings demonstrate that bulk polymer characteristics can be tuned, a highly desirable attribute for many nanocomposite materials.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Intercalation of quaternary ammonium cations as a key factor of electron storage in MoS2 thin films

Electrochemical intercalation of cations within two-dimensional transition metal dichalcogenides presents a promising route for tailoring their optoelectronic properties. We have now succeeded in modulating the optical properties of MoS2 thin films through electrochemical intercalation of quaternary ammonium cations. The spectroelectrochemical experiments conducted with varying sizes of the intercalant revealed the size-dependent stability of the intercalated MoS2 nanosheets. The observed absorption change of the exciton bands is reversible and arises from the storage of electrons in MoS2 nanosheets and the subsequent weakening of interlayer van der Waals interactions following cation intercalation. This structural change is evidenced by the emergence of A*1g out-of-plane Raman mode. Additionally, the photoelectron spectroscopy reveals the emergence of a lower binding energy component of Mo 3d and the shift in Fermi level to higher energies, confirming the presence of stored electrons in cation intercalated-MoS2. The underlying mechanism of intercalation-induced property modifications in MoS2 discussed in the present study is useful in developing strategies for energy conversion devices.

Physics↗
DOE OSTI2025

Stable Diacid Coordinated Quaternary Ammonium Polymers for 80-230 °C Fuel Cells

Current automotive fuel cells that use sulfonated polymer-based proton exchange membranes are challenging to operate at > 100 °C without humidification. In this project, we developed polymer electrolyte fuel cells that run at > 100 °C without humidification using a novel class of proton exchange membranes made from thermos-oxidatively stable acid-coordinated quaternary ammonium polymers. These fuel cells remove the external humidifiers/demisters and reduce the size of radiators, thus vastly simplifying fuel cell integration, which increases tolerance to impurities and improves electrode kinetics of catalysts. Operating fuel cells without hydration has a significant benefit on fuel cell cost and economic feasibility was investigated by comparing existing fuel cell systems. This project bridges the scale-up process to manufacture the fuel cell component through the U.S. DOE L’Innovator project sponsored by the U.S. DOE Hydrogen and Fuel Cell Technologies Office (HFTO).

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2024

Quaternary ammonium salt coated air filter for bioaerosol removal from building indoor air

Developing air filters with biocidal ability is important to protect the public from infectious respiratory diseases. A simple spray-coating approach was devised to fabricate antimicrobial air filters to remove bioaerosols. Here, the commercial antimicrobial agent Goldshield 75 was coated on the air filters through covalent immobilization, endowing the fabricated filter with long-lasting biocidal ability. All coated filters significantly inhibited both Gram-positive bacteria (Micrococcus luteus) and Gram-negative bacteria (Escherichia coli). The antibacterial ability of the coated filters is similar to the commercial AeraSafe antibacterial filter. The coated filter showed over 99.9 % antibacterial efficiency 3 months after the application of the coating. Both bacterial and virus filtration efficiencies of coated charged polypropylene filter were higher than 99.9 %. The coating did not have much effect on the NaCl aerosol filtration efficiency of the filters. This simple spray-coating strategy is a practical method for producing antimicrobial air filters for the prevention of infectious respiratory diseases.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Synthesis and Characterization of Homoleptic Rare Earth Nitrato Complexes with the Quaternary Ammonium Cations Et 4 N + and n Pr 4 N +

Two periodic series of homoleptic rare earth nitrato com plexes, [R 4 N] x [M(NO 3 ) y ](M = La-Nd, Sm-Lu, Y); R = Et, $n$ Pr; x = 2-3; y = 5-6) have been synthesized, and charac terized by single crystal X-ray diffraction, IR and Raman spectroscopy, comparing the solid state speciation of the nitrate ions as a function of lanthanide ion and quarternary ammonium cation. The series of the form [Et 4 N] 3 [Ln(NO 3 ) 6 ] crystallizes in the rhombohedral space group $R$$\bar{3}$, as a twelve-coordinate hexanitrato complex [Et 4 N] 3 [Ln(NO 3 ) 6 ] with cocrystallized HNO 3 for La, Pr, and Nd. For Ce, a distinct orthorhombic phase retaining the same formula, [Et 4 N] 3 [Ce(NO 3 ) 6 ] is isolated in the absence of HNO 3 to prevent oxidation of the Ce(III) to Ce(IV) in nitric acid. A ten-coordinate pentanitrato complex, [Et 4 N] 2 [Ln(NO 3 ) 5 ], in monoclinic symmetry forms for the remainder of the series, and for Y(III). The entire series crystallized in the presence of [ $n$ Pr 4 N] + counterions forms a pentanitrato complex [ $n$ Pr 4 N] 2 [M(NO 3 ) 5 ] in the orthorhombic space group, $Pccn$. In conclusion, analysis of trends in the structural and spectroscopic characteristics of these series reveal insight into the structure directing influences of both the lanthanide contraction and the quarternary ammonium cations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Anion-exchanged and quaternary ammonium functionalized MIL-101-Cr metal-organic framework (MOF) for ReO 4 – /TcO 4 – sequestration from groundwater

There are few effective technologies for the sequestration of highly water-soluble pertechnetate (TcO 4 – ) from contaminated water despite the urgency of environmental and public health concerns. Here, anion exchanged and cetyltrimethylammonium bromide (CTAB) functionalized MIL-101-Cr-NO 3 were investigated for perrhenate (ReO 4 – ), a surrogate of TcO 4 – , sequestration from artificial groundwater. Cl – , I – , and CF 3 SO 3 – exchanged MIL-101-Cr proved more effective at ReO 4 – removal than the parent MIL-101-Cr-F. Compared to the parent framework, CTAB functionalized MIL-101-Cr-NO 3 increased ReO 4 – removal capacity from 39 to 139 mg/g, improved the reaction kinetics from ~30 to <10 min to reach full adsorption capacity and the selectivity for ReO 4 – over competing NO 3 – , CO 3 2– , SO 4 2– , and Cl – . Spectroscopic data indicated that the chemical speciation of Re in the exchanged MIL-101-Cr remained ReO 4 – , indicating synergistic sequestration through both anion exchange and non-ion exchange binding with the positively charged ligand of CTAB. These studies foreshadow potential applications of MOFs for the remediation of 99 TcO 4 – from contaminated environments.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2023

Energetic Insights into the Role of Quaternary Ammonium Cations in Zeolite Synthesis

The thermodynamics of partitioning of an organic structure-directing agent (OSDA) between water and an organic solvent such as chloroform or trichloroethane serve as a proxy for energetic interactions during zeolite synthesis. Using several newly synthesized OSDAs, we have extended our earlier calorimetric and partitioning studies of the thermodynamics of transfer to separate effects of charge (C/N + ratio) and structure in a series of structurally related OSDAs. The Gibbs free energies of transfer are close to zero, resulting from a balance of strongly exothermic and relatively similar enthalpies and strongly negative and relatively similar entropies of transfer. There is no obvious correlation between the thermodynamics of transfer and the efficacy of a given OSDA in the zeolite synthesis. Finally, one must conclude that with bulk energetics of transfer being similar in most cases studied, the critical factors in OSDA function in zeolite synthesis are kinetically rather than thermodynamically controlled and arise from differences in activation energies related to details of OSDA structure and interactions during nucleation of possible zeolite precursors.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Ionic liquids containing quaternary ammonium and phosphonium cations, and their use as environmentally friendly lubricant additives

An ionic liquid composition having the following generic structural formula: wherein Z is N or P, and R 1 , R 2 , R 3 , and R 4 are independently selected from hydrogen atom and hydrocarbon groups having one to four carbon atoms with optional interconnection to form a cyclic group that includes Z, and wherein R 1 , R 2 , R 3 , and R 4 are all hydrocarbon groups when Z is P, and X− is a phosphorus-containing or carboxylate anion, particularly an organophosphate, organophosphonate, or organophosphinate anion, or a thio-substituted analog thereof containing hydrocarbon groups with at least three carbon atoms. Also described are lubricant compositions comprising the above ionic liquid and a base lubricant, wherein the ionic liquid is dissolved in the base lubricant. Further described are methods for applying the ionic liquid or lubricant composition onto a mechanical device for which lubrication is beneficial, with resulting improvement in friction reduction, wear rate, and/or corrosion inhibition.

Qu, Jun↗
DOE OSTI2020

Porosity and hydrophilicity modulated quaternary ammonium-based sorbents for CO 2 capture

Quaternary ammonium (QA)-based polymeric sorbents are known to be effective for CO 2 capture, especially from ultradilute streams like air. In this work, we address two major challenges in QA sorbent design for application in moisture-swing processes, porosity control and hydrophilicity modulation. Facilely substituting porous CO 2 -active components for non-porous ones can enhance the sorption kinetics by 4-fold compared to the state-of-art, and micro–mesoporous structures are identified as optimal porous structures. A method to modulate the hydrophilicity of QA-based sorbents is developed using controlled radical polymerization, incorporating fluorine-containing monomers. The CO 2 sorption capacity and the tolerance towards moisture are simultaneously enhanced via adjustment of the structure and the content of fluorine-containing blocks. Finally, we postulate that porosity and hydrophilicity optimization can make QA-based sorbents adaptive to deployment of scalable moisture-swing processes in varied and complex atmospheric circumstances.

42 ENGINEERING↗