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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.

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At least 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Salt Transport in Crosslinked Hydrogel Membranes Containing Zwitterionic Sulfobetaine Methacrylate and Hydrophobic Phenyl Acrylate

Produced water is a by-product of industrial operations, such as hydraulic fracturing for increased oil recovery, that causes environmental issues since it includes different metal ions (e.g., Li+, K+, Ni2+, Mg2+, etc.) that need to be extracted or collected before disposal. To remove these substances using either selective transport behavior or absorption-swing processes employing membrane-bound ligands, membrane separation procedures are promising unit operations. This study investigates the transport of a series of salts in crosslinked polymer membranes synthesized using a hydrophobic monomer (phenyl acrylate, PA), a zwitterionic hydrophilic monomer (sulfobetaine methacrylate, SBMA), and a crosslinker (methylenebisacrylamide, MBAA). Membranes are characterized according to their thermomechanical properties, where an increased SBMA content leads to decreased water uptake due to structural differences within the films and to more ionic interactions between the ammonium and sulfonate moieties, resulting in a decreased water volume fraction, and Young’s modulus increases with increasing MBAA or PA content. Permeabilities, solubilities, and diffusivities of membranes to LiCl, NaCl, KCl, CaCl2, MgCl2, and NiCl2 are determined by diffusion cell experiments, sorption-desorption experiments, and the solution-diffusion relationship, respectively. Permeability to these metal ions generally decreases with an increasing SBMA content or MBAA content due to the corresponding decreasing water volume fraction, and the permeabilities are in the order of K+ > Na+ > Li+ > Ni2+ > Ca2+ > Mg2+ presumably due to the differences in the hydration diameter.

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

Redox enzyme-embedded pyrene-poly(ethylenimine) hydrogel electrode for electrosynthesis

Devices, systems, and compositions of matter involving enzyme-mediated bioelectrocatalysis are disclosed and described. An enzyme electrode can include an electrode, a bioelectric material coupled to the electrode, the bioelectric material further including a water-permeable polymer matrix, a planar linker covalently coupled to the water-permeable polymer matrix and noncovalently coupled to the electrode, and electrochemically active oxidoreductase enzyme molecules functionally embedded in the water-permeable polymer matrix.

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

Computational Prediction of Coiled–Coil Protein Gelation Dynamics and Structure

Protein hydrogels represent an important and growing biomaterial for a multitude of applications, including diagnostics and drug delivery. We have previously explored the ability to engineer the thermoresponsive supramolecular assembly of coiled–coil proteins into hydrogels with varying gelation properties, where we have defined important parameters in the coiled–coil hydrogel design. Using Rosetta energy scores and Poisson–Boltzmann electrostatic energies, we iterate a computational design strategy to predict the gelation of coiled–coil proteins while simultaneously exploring five new coiled–coil protein hydrogel sequences. Provided this library, we explore the impact of in silico energies on structure and gelation kinetics, where we also reveal a range of blue autofluorescence that enables hydrogel disassembly and recovery. As a result of this library, we identify the new coiled–coil hydrogel sequence, Q5, capable of gelation within 24 h at 4 °C, a more than 2-fold increase over that of our previous iteration Q2. The fast gelation time of Q5 enables the assessment of structural transition in real time using small-angle X-ray scattering (SAXS) that is correlated to coarse-grained and atomistic molecular dynamics simulations revealing the supramolecular assembling behavior of coiled–coils toward nanofiber assembly and gelation. This work represents the first system of hydrogels with predictable self-assembly, autofluorescent capability, and a molecular model of coiled–coil fiber formation.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Engineering Calcium-Bearing Mineral/Hydrogel Composites for Effective Phosphate Recovery

Effectively recovering phosphate from wastewater streams and reutilizing it as a nutrient will critically support sustainability. Here, to capture aqueous phosphate, we developed novel mineral-hydrogel composites composed of calcium alginate, calcium phosphate (CaP), and calcium silicate (CSH) (CaP + CSH/Ca-Alg). The CaP + CSH/Ca-Alg composites were synthesized by dripping a sodium alginate (Na-Alg) solution with ionic precursors into a calcium chloride bath. To change the mineral seed’s properties, we varied the calcium bath concentrations and the ionic precursor (sodium dibasic phosphate (NaH 2 PO 4 ) and/or sodium silicate (Na 2 SiO 3 )) amounts and their ratios. The added CSH in the mineral-hydrogel composites resulted in the release of calcium and silicate ions in phosphate-rich solutions, increasing the saturation ratio with respect to calcium phosphate within the mineral-hydrogel composites. The CSH addition to the mineral-hydrogel composites doubled the phosphate removal rate while requiring lesser initial amounts of Ca and P materials for synthesis. Furthermore, by incorporating both CSH and CaP mineral seeds in composites, we achieved a final concentration of 0.25 mg-P/L from an initial 6.20 mg-P/L. Moreover, the mineral-hydrogel composites can remove phosphate even under CaP undersaturated conditions. This suggests their potential to be a widely applicable and environmentally-sustainable treatment and recovery method for nutrient-rich wastewater.

42 ENGINEERING↗
DOE OSTI2019

Drawing with Iron on a Gel Containing a Supramolecular Siderophore

Guanosine-5'-hydroxamic acid (3) forms hydrogels when mixed with guanosine (1) and KCl. The 5'-hydroxamic acid (HA) unit is pH-responsive and also chelates Fe 3+ . When gels are prepared under basic conditions, the 5'-HA groups are deprotonated and the anionic hydrogel binds cationic thiazole orange (TO), signaled by enhanced fluorescence. The HA nucleoside 3, when immobilized in the G-quartet gel, acts as a supramolecular siderophore to form red complexes with Fe 3+ . We patterned the hydrogel's surface with FeCl 3 , by hand and by using a 3D printer. Patterns form instantly, are visible by eye, and can be erased using vitamin C. This hydrogel, combining self-assembled G-quartet and siderophore–Fe 3+ motifs, is strong, can be molded into different shapes, and is stable on the bench or under salt water.

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

“Water–in–Eutectogel” Electrolytes for Quasi–Solid–State Aqueous Lithium–Ion Batteries

The development of high safety lithium-ion batteries (LIBs) is greatly impeded by the flammability and leakage concerns of typical organic solvent-based electrolytes. As one of the alternative classes of electrolytes, hydrogel electrolytes exhibit high safety, high flexibility, low cost, and are benign to the environment. However, the narrow electrochemical stability window (ESW) of typical hydrogel electrolytes restricts the operating voltage of battery cells. Here, a new class of “water-in-eutectogel (WiETG)” electrolyte is reported, fabricated by combining a hydrogel with a “deep eutectic solvent” (LiTFSI in acetamide). The obtained WiETG electrolyte exhibits non-flammability, high ionic conductivity, and a wide ESW. LiMn 2 O 4 ||Li 4 Ti 5 O 12 cells with the WiETG electrolyte exhibit good cycling stability, high flexibility, and high safety. This newly developed WiETG electrolyte not only broadens the ESW of typical hydrogel electrolytes, but also opens a new perspective on future directions and guidance for the design of high safety electrolytes for flexible LIBs and beyond.

25 ENERGY STORAGE↗