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Title: Polymers in molten inorganic salt hydrate phase change materials: solubility and gelation

Journal Article · · Journal of Materials Chemistry. A
DOI:https://doi.org/10.1039/d1ta07842a· OSTI ID:1978842

Inorganic salt hydrates are of interest as phase change materials (PCMs) for thermal energy storage because of their unique properties, such as high latent heats of fusion, moderate melting temperatures, high volumetric energy storage densities, and enhanced thermal conductivities compared to their organic counterparts. Because of the low viscosities of molten salt hydrates, the leakage and settling of solids can easily occur during their application. Polymers are promising candidates for preventing these issues. In addition, the non-flammability, non-volatility, and nontoxicity of many molten salt hydrates make them attractive options as “green” solvents for polymers. However, solutions of polymers in molten salt hydrates have rarely been studied and are poorly understood. The highly ionic environments in these materials created due to a scarcity of hydration water for ions leads to strong ionic interactions, with ramifications for polymer solubility and chain expansion. This Perspective article aims to focus on polymer solutions and gels in inorganic salt hydrates by comparing these systems with existing knowledge of polymers in traditional ionic liquids and aqueous salt solutions. To provide insight into the states of ions and water in molten salt hydrates and the degree of hydration of polymers in these solvents, infrared spectroscopy experiments have been performed, and the data are correlated with the temperature-responsive gelation of poly(vinyl alcohol), one candidate material currently used for the shape stabilization of inorganic PCMs. Finally, the thermal properties of inorganic salt hydrates and ionic liquids are compared and strategies for the shape stabilization of inorganic salt hydrates using polymers, through the formation of physical gels, are discussed.

Research Organization:
Texas A & M Univ., College Station, TX (United States). Texas A & M Engineering Experiment Station
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE); National Science Foundation (NSF)
Grant/Contract Number:
EE0009155; 1847956
OSTI ID:
1978842
Alternate ID(s):
OSTI ID: 1832054
Journal Information:
Journal of Materials Chemistry. A, Vol. 9, Issue 46; ISSN 2050-7488
Publisher:
Royal Society of ChemistryCopyright Statement
Country of Publication:
United States
Language:
English

References (185)

A review on current status and challenges of inorganic phase change materials for thermal energy storage systems journal April 2017
Thermal energy storage for solar heating and off-peak air conditioning journal January 1975
The Hydration Number of Li + in Liquid Water journal February 2000
Review: Current studies on some physical properties of ionic liquids journal December 2003
A facile strategy to fabricate highly-stretchable self-healing poly(vinyl alcohol) hybrid hydrogels based on metal–ligand interactions and hydrogen bonding journal January 2016
Ultrasonic Velocities, Densities, Viscosities, Electrical Conductivities, Raman Spectra, and Molecular Dynamics Simulations of Aqueous Solutions of Mg(OAc) 2 and Mg(NO 3 ) 2 :  Hofmeister Effects and Ion Pair Formation journal December 2005
The present state of affairs with Hofmeister effects journal August 2004
Corrosion behaviour of ionic liquids journal January 2005
Shape-Stable Hydrated Salts/Polyacrylamide Phase-Change Organohydrogels for Smart Temperature Management journal April 2021
Thermodynamic properties and phase transitions of salt hydrates between 270 and 400 K III. CH3CO2Na·3H2O, CH3CO2Li·2H2O, and (CH3CO2)2Mg·4H2O journal June 1984
Structure of Ionic Liquid−Benzene Mixtures journal February 2005
Zur Lehre von der Wirkung der Salze: Zweite Mittheilung journal February 1888
Structural aspects of the LCST phase behavior of poly(benzyl methacrylate) in room-temperature ionic liquid journal March 2011
Coil Dimensions of Poly(ethylene oxide) in an Ionic Liquid by Small-Angle Neutron Scattering journal October 2017
The Raman OH stretching bands of liquid water journal November 2009
Low temperature latent heat thermal energy storage: Heat storage materials journal January 1983
Solar thermal energy storage based on sodium acetate trihydrate phase change hydrogels with excellent light-to-thermal conversion performance journal December 2018
Condensed phase behaviour of ionic liquid–benzene mixtures: congruent melting of a [emim][NTf 2 ]·C 6 H 6 inclusion crystal journal January 2006
Energy applications of ionic liquids journal January 2014
Use of ionic liquids in sol-gel; ionogels and applications journal January 2010
Thermal performance of sodium acetate trihydrate thickened with different materials as phase change energy storage material journal September 2003
A Supercooled Imidazolium Iodide Ionic Liquid as a Low-Viscosity Electrolyte for Dye-Sensitized Solar Cells journal November 2006
Thermophysical Properties of Lithium Nitrate Trihydrate from (253 to 353) K journal April 2012
Enhanced thermal properties of hydrate salt/poly (acrylate sodium) copolymer hydrogel as form-stable phase change material via incorporation of hydroxyl carbon nanotubes journal May 2020
Ion-solvent interaction and the viscosity of strong-electrolyte solutions journal January 1957
Critical examination and experimental determination of melting enthalpies and entropies of salt hydrates journal September 1983
Preparation and properties of a form-stable phase-change hydrogel for thermal energy storage journal May 2016
The Entropy of Dilution of Strong Electrolytes in Aqueous Solutions journal December 1940
Why Are Ionic Liquids Liquid? A Simple Explanation Based on Lattice and Solvation Energies journal October 2006
Characterization of PVdF(HFP) Gel Electrolytes Based on 1-(2-Hydroxyethyl)-3-methyl Imidazolium Ionic Liquids journal September 2005
Conformational and Dynamic Properties of Poly(ethylene oxide) in BMIM + BF 4 : A Microsecond Computer Simulation Study Using ab Initio Force Fields journal July 2018
Review on thermal performances and applications of thermal energy storage systems with inorganic phase change materials journal December 2018
Application of ionic liquids as solvents for polymerization processes journal January 2004
Graphene oxide modified hydrate salt hydrogels: form-stable phase change materials for smart thermal management journal January 2016
Upper critical solution temperature (UCST) phase transition of halide salts of branched polyethylenimine and methylated branched polyethylenimine in aqueous solutions journal January 2016
Unconventional Deep Eutectic Solvents: Aqueous Salt Hydrates journal November 2017
Review of Cellulose Non-Derivatizing Solvent Interactions with Emphasis on Activity in Inorganic Molten Salt Hydrates journal May 2013
Tuning of thermal properties of sodium acetate trihydrate by blending with polymer and silver nanoparticles journal January 2014
Solvation and diffusion of poly(vinyl alcohol) chains in a hydrated inorganic ionic liquid journal January 2020
Simultaneous solar-thermal energy harvesting and storage via shape stabilized salt hydrate phase change material journal February 2021
Ion Gel Membrane with Tunable Inorganic/Organic Composite Network for CO 2 Separation journal October 2017
Poly( n -butyl methacrylate) in Ionic Liquids with Tunable Lower Critical Solution Temperatures (LCST) journal March 2011
Pulsed Laser Polymerization in an Ionic Liquid:  Strong Solvent Effects on Propagation and Termination of Methyl Methacrylate journal June 2003
On the fusion of liquids with spherical- and linear-like molecules journal June 1979
Advanced Materials for Energy Storage journal February 2010
Room temperature ionic liquids and their mixtures—a review journal May 2004
Review on thermal energy storage with phase change: materials, heat transfer analysis and applications journal February 2003
Unusual Lower Critical Solution Temperature Phase Behavior of Poly(ethylene oxide) in Ionic Liquids journal April 2012
Review on shell materials used in the encapsulation of phase change materials for high temperature thermal energy storage journal August 2015
Nuclear Magnetic Resonance Effects in Aqueous Solutions of 1–1 Electrolytes journal February 1962
CHEMISTRY: Ionic Liquids--Solvents of the Future? journal October 2003
Heterogeneous nucleation from a supercooled ionic liquid on a carbon surface journal December 2016
Microscopic Structure of Solvated Poly(benzyl methacrylate) in an Imidazolium-Based Ionic Liquid: High-Energy X-ray Total Scattering and All-Atom MD Simulation Study journal June 2017
Raman and infrared spectra study of magnesium nitrate-water systems journal January 1973
Protic Ionic Solids and Liquids Based on the Guanidinium Cation as Phase-Change Energy-Storage Materials journal September 2013
Theoretical study of small water clusters: low-energy fused cubic structures for (H2O)n, n = 8, 12, 16, and 20 journal May 1993
Lower Critical Solution Temperature Behavior of Linear Polymers in Ionic Liquids and the Corresponding Volume Phase Transition of Polymer Gels journal January 2007
Vibrational spectroscopic study of aqueous cadmium nitrate solutions journal December 1968
A Raman Spectrophotometric Comparison of Interionic Association in Aqueous Solutions of Metal Nitrates, Sulfates, and Perchlorates journal May 1964
Salt hydrates used for latent heat storage: Corrosion of metals and reliability of thermal performance journal January 1988
Chemistry of salts in aqueous solutions: Applications, experiments, and theory journal April 2011
Environmental fate and toxicity of ionic liquids: A review journal January 2010
Ionogels, ionic liquid based hybrid materials journal January 2011
Far-ultraviolet resonance Raman spectroscopy of nitrate ion in solution journal October 2000
Preparation and thermal characterization of sodium acetate trihydrate/expanded graphite composite phase change material journal April 2016
Review of solid–liquid phase change materials and their encapsulation technologies journal August 2015
Cationic clustering influences the phase behaviour of ionic liquids journal October 2018
Types of Interaction in Some Aqueous Metal Nitrate Systems journal March 1969
Vibrational Spectroscopic Study of Contact Ion Pairing between Zn ++ and NO 3 in Water journal December 1966
Water-soluble polymer–metal ion interactions journal February 2003
Review on form-stable inorganic hydrated salt phase change materials: Preparation, characterization and effect on the thermophysical properties journal June 2021
Thermal stability of phase change materials used in latent heat energy storage systems: A review journal February 2013
Effects of Hofmeister Anions on the LCST of PNIPAM as a Function of Molecular Weight journal June 2007
A review of microencapsulation methods of phase change materials (PCMs) as a thermal energy storage (TES) medium journal March 2014
Synthesis of Polyacrylamide with Superb Salt-Thickening Performance journal October 2015
Review on thermal energy storage with phase change materials and applications journal February 2009
Thermal energy storage in salt hydrates journal July 1980
Upper Critical Solution Temperature Behavior of Poly( N -isopropylacrylamide) in an Ionic Liquid and Preparation of Thermo-sensitive Nonvolatile Gels journal August 2006
Hydrated Salt/Graphite/Polyelectrolyte Organic-Inorganic Hybrids for Efficient Thermochemical Storage journal March 2019
Water: From Clusters to the Bulk journal May 2001
Thermodynamic properties and phase transitions of salt hydrates between 270 and 400 K I. NH4Al(SO4)2 · 12H2O, KAl(SO4)2 · 12H2O, Al2(SO4)3 · 17H2O, ZnSO4 · 7H2O, Na2SO4 · 10H2O, and Na2S2O3 · 5H2O journal November 1982
Hydration Dynamics of Aqueous Nitrate journal March 2013
Interactions in aqueous alkali metal nitrate solutions journal March 1968
Effect of solvent hydrophobicity on gelation kinetics and phase diagram of gelatin ionogels journal January 2014
Macromolecules in Ionic Liquids: Progress, Challenges, and Opportunities journal June 2008
Solvation Structure of Poly(ethylene glycol) in Ionic Liquids Studied by High-energy X-ray Diffraction and Molecular Dynamics Simulations journal March 2013
Morphology of Poly(ethylene oxide) Dissolved in a Room Temperature Ionic Liquid:  A Small Angle Neutron Scattering Study journal February 2006
Conformational and Dynamic Properties of Poly(ethylene oxide) in an Ionic Liquid: Development and Implementation of a First-Principles Force Field journal December 2015
Vibrational Spectra of Molten Salts. I. Infrared Spectra of Calcium Nitrate in Alkali‐Metal Nitrate Solutions journal May 1967
Difference in Lower Critical Solution Temperature Behavior between Random Copolymers and a Homopolymer Having Solvatophilic and Solvatophobic Structures in an Ionic Liquid journal May 2007
Skeleton materials for shape-stabilization of high temperature salts based phase change materials: A critical review journal March 2020
Prevention of supercooling and stabilization of inorganic salt hydrates as latent heat storage materials journal July 1992
Lower Critical Solution Temperature (LCST) Phase Behavior of Poly(ethylene oxide) in Ionic Liquids journal June 2010
Hopes for Hofmeister journal November 1995
Thermophysical Properties of Potassium Fluoride Tetrahydrate from (243 to 348) K journal January 2013
Effect of Ionic Liquid Components on the Coil Dimensions of PEO journal April 2019
Hydrophobic and polar ionic liquids journal January 2013
Inorganic salt hydrate for thermal energy storage application: A review journal October 2020
Increasing contact ion pairing in the supercooled and glassy states of "dilute" aqueous magnesium, calcium, and strontium nitrate solution: implications for biomolecules journal May 1993
Heat transfer enhancement of phase change materials for thermal energy storage applications: A critical review journal July 2017
Thermal properties of imidazolium ionic liquids journal August 2000
Hydrate salt/self‐curing acrylic resin form‐stable phase change materials with enhanced surface stability and thermal properties via the incorporation of graphene oxide journal March 2020
Development of phase change materials based microencapsulated technology for buildings: A review journal February 2011
Solid–liquid equilibria in mixtures of molten salt hydrates for the design of heat storage materials journal January 2002
Thermodynamical properties of phase change materials based on ionic liquids journal April 2009
Atomistic Simulations of Poly(ethylene oxide) in Water and an Ionic Liquid at Room Temperature journal December 2013
High temperature corrosion properties of ionic liquids journal September 2006
Evaluation of toxicity and biodegradability for cholinium-based deep eutectic solvents journal January 2015
Printable ion-gel gate dielectrics for low-voltage polymer thin-film transistors on plastic journal October 2008
Corrosive effects of salt hydrate phase change materials used with aluminium and copper journal June 2006
Coordination of water to magnesium cations journal February 1994
Heterogeneous nucleation of thermal storage material LiNO3·3H2O from stable lattice-matched nucleation catalysts journal February 2015
Effects of Hofmeister Anions on the Phase Transition Temperature of Elastin-like Polypeptides journal November 2008
Conformation of Poly(ethylene oxide) Dissolved in Ethylammonium Nitrate journal February 2011
Drawing out the structural information of the first layer of hydrated ions: ATR-FTIR spectroscopic studies on aqueous NH4NO3, NaNO3, and Mg(NO3)2 solutions journal March 2005
Raman and Infrared Spectral Studies of Aqueous Calcium Nitrate Solutions journal January 1967
Specific Ion Effects: Why DLVO Theory Fails for Biology and Colloid Systems journal October 2001
Micelle/Inverse Micelle Self-Assembly of a PEO−PNIPAm Block Copolymer in Ionic Liquids with Double Thermoresponsivity journal November 2010
Solution behavior and associating structures of a salt-tolerant tetra-polymer containing an allyl-capped macromonomer journal November 2014
Salt hydrate/expanded vermiculite composite as a form-stable phase change material for building energy storage journal January 2019
Immersion corrosion tests on metal-salt hydrate pairs used for latent heat storage in the 32 to 36°C temperature range journal February 2001
Development of a stable inorganic phase change material for thermal energy storage in buildings journal May 2020
Characterization of calcium chloride tetrahydrate as a phase change material and thermodynamic analysis of the results journal September 2016
Densities of Solid and Molten Salt Hydrates and Their Mixtures and Viscosities of the Molten Salts journal September 2004
Corrosion of steel in ionic liquids journal January 2003
Raman Spectrophotometric Study of Complex Formation in Aqueous Solutions of Calcium Nitrate journal January 1964
Aqueous divalent metal–nitrate interactions: hydration versus ion pairing journal January 2008
Looking at the “Water-in-Deep-Eutectic-Solvent” System: A Dilution Range for High Performance Eutectics journal October 2019
Anhydrous Proton Conducting Polymer Electrolyte Membranes via Polymerization-Induced Microphase Separation journal February 2016
A triple thermoresponsive schizophrenic diblock copolymer journal January 2013
Infrared Spectroscopy of the Microhydrated Nitrate Ions NO 3 (H 2 O) 1−6 journal July 2009
Specific Ion Effects on the Water Solubility of Macromolecules:  PNIPAM and the Hofmeister Series journal October 2005
Raman spectroscopic investigation of the magnesium nitrate-water system journal March 1972
Proton-conducting polymer electrolyte membranes based on hydrocarbon polymers journal December 2000
Fatty acid eutectic/polymethyl methacrylate composite as form-stable phase change material for thermal energy storage journal August 2010
Conformation of poly(ethylene oxide) dissolved in the solvate ionic liquid [Li(G4)]TFSI journal January 2015
Polymers in Ionic Liquids: Dawn of Neoteric Solvents and Innovative Materials journal January 2012
Review of stability and thermal conductivity enhancements for salt hydrates journal August 2019
A salt-induced viscosifying smart polymer for fracturing inter-salt shale oil reservoirs journal May 2019
A low temperature fused salt experiment: The conductivity, viscosity, and density of molten calcium nitrate tetrahydrate journal September 1967
Thermal property and latent heat energy storage behavior of sodium acetate trihydrate composites containing expanded graphite and carboxymethyl cellulose for phase change materials journal January 2015
Thermoreversible Ion Gels with Tunable Melting Temperatures from Triblock and Pentablock Copolymers journal January 2008
Polyvinyl Alcohol-salt Hydrate Mixtures as Passive Thermal Energy Storage Systems journal June 2016
Complex formation between poly(vinyl alcohol) and metallic ions in aqueous solution journal January 1974
Lower Critical Solution Temperature Phase Behavior of Poly( n -butyl methacrylate) in Ionic Liquid Mixtures journal November 2013
Corrosion of metals and salt hydrates used for thermochemical energy storage journal March 2015
The entropy change on melting of simple substances journal March 1980
Sugar–Metal Ion Interactions: The Complicated Coordination Structures of Cesium Ion with d -Ribose and myo -Inositol journal October 2013
Systematic review of encapsulation and shape-stabilization of phase change materials journal August 2020
Shape-stabilized phase change materials based on porous supports for thermal energy storage applications journal January 2019
Thermal conductivity enhancement of phase change materials for thermal energy storage: A review journal September 2016
Phase change performance of sodium acetate trihydrate with AlN nanoparticles and CMC journal September 2011
Thermochemistry of ionic liquid heat-transfer fluids journal January 2005
Apparent Volumes of Individual Ions in Aqueous Solution 1 journal March 1942
A review on phase change energy storage: materials and applications journal June 2004
A review of salt hydrates for seasonal heat storage in domestic applications journal August 2017
Crystallization and Rheology of Poly(ethylene oxide) in Imidazolium Ionic Liquids journal August 2016
Calcium Ion Coordination:  A Comparison with That of Beryllium, Magnesium, and Zinc journal January 1996
Synthesis and application of starch-graft-poly(AM-co-AMPS) by using a complex initiation system of CS-APS journal May 2007
Mechanically Tunable, Readily Processable Ion Gels by Self-Assembly of Block Copolymers in Ionic Liquids journal September 2016
Nucleation triggering methods in supercooled phase change materials (PCM), a review journal December 2018
Miscibility and phase behavior of water–dicarboxylic acid type ionic liquid mixed systems journal January 2007
Dispersion polymerization of acrylamide with 2-acrylamide-2-methyl-1-propane sulfonate in aqueous solution of sodium sulfate journal December 2008
Supercooling salt hydrates: Stored enthalpy as a function of temperature journal May 2006
Anion effects on ionogel formation in N,N′-dialkylimidazolium-based ionic liquids journal November 2004
UV-Initiated Polymerization of Hydrophobically Associating Cationic Polyacrylamide Modified by a Surface-Active Monomer: A Comparative Study of Synthesis, Characterization, and Sludge Dewatering Performance journal June 2014
Nanoencapsulation of phase change materials (PCMs) and their applications in various fields for energy storage and management journal September 2020
Thermosensitive Phase Separation Behavior of Poly(benzyl methacrylate)/Solvate Ionic Liquid Solutions journal December 2017
Interactions between macromolecules and ions: the Hofmeister series journal December 2006
Graphene-Modified Hydrate Salt/UV-Curable Resin Form-Stable Phase Change Materials: Continuously Adjustable Phase Change Temperature and Ultrafast Solar-to-Thermal Conversion journal July 2019
Inorganic Salt Hydrate for Thermal Energy Storage journal December 2017
Self-Healing Phase Change Salogels with Tunable Gelation Temperature journal April 2018
Vibrational Spectral Studies of Hexaquozinc Nitrate and Hexaquozinc Nitrate- d 2 journal May 1971
Properties of ionic liquid solvents for catalysis journal May 2004
Cation-nitrate ion contact in aqueous solutions journal February 1970
Preparation and characterization of side-chain liquid crystal polymer/paraffin composites as form-stable phase change materials journal January 2015
Thermodynamic study on phase transitions of poly(benzyl methacrylate) in ionic liquid solvents journal September 2009
Ionic Interactions in Aqueous Solution: A Raman Spectral Study journal November 1963
Novel semi-interpenetrating network structural phase change composites with high phase change enthalpy journal September 2017
Phase behaviour and solution properties of sulphobetaine polymers journal November 1986
Raman and ultrasonic relaxation studies of some nitrate salts in N-methylacetamide journal June 1981
Hydrated salts/expanded graphite composite with high thermal conductivity as a shape-stabilized phase change material for thermal energy storage journal September 2015
Thermodynamic properties and phase transitions of salt hydrates between 270 and 400 K IV. CaCl2·6H2O, CaCl2·4H2O, CaCl2·2H2O, and FeCl3·6H2O journal February 1986
Review on storage materials and thermal performance enhancement techniques for high temperature phase change thermal storage systems journal May 2012
Luminescent Ionogels Based on Europium-Doped Ionic Liquids Confined within Silica-Derived Networks journal November 2006

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