Supercooled State Research Articles

Melting Temperature Hidden Behind Liquid-Liquid Phase Transition in Glycerol.

Liquid-liquid phase transitions play a pivotal role in various scientific disciplines and technological applications, ranging from biology to materials science and geophysics. Understanding the behavior of materials undergoing these transitions provides valuable insights into complex systems and their dynamic properties. This review explores the implications of liquid-liquid phase transitions, particularly focusing on the transition between low-density liquid (LDL) and high-density liquid (HDL) phases. We investigate the thermodynamic, structural, and mechanistic aspects of these transitions, emphasizing their relevance in diverse fields. The creation of dynamic heterogeneities and critical fluctuations during liquid-liquid phase transitions is discussed, highlighting their role in shaping the phase behavior and dynamics of complex fluids. Experimental observations, including the use of dielectric spectroscopy and nonlinear methods, shed light on the intricate nature of these transitions. Our findings suggest a connection between liquid-liquid phase transitions and critical phenomena, with implications for understanding the supercooled state and phase behavior of hydrogen-bonded liquids such as glycerol. Overall, this review underscores the importance of interdisciplinary approaches in unraveling the complexities of liquid-liquid phase behavior and addressing fundamental questions.

Effect of oscillating magnetic field (OMF) on the supercooling behavior of iron-oxide nanoparticle (IONP) agar model system.

Freezing extends the shelf life of foods but often leads to structural damage due to ice crystal formation, negatively impacting quality attributes. Oscillating magnetic field (OMF)-assisted supercooling has emerged as a potential technique to overcome these limitations by inhibiting ice nucleation and maintaining foods in a supercooled state. Despite its potential, the effectiveness and underlying mechanisms of OMF-assisted supercooling remain subjects of debate. In this study, the effects of OMF on the supercooling behavior of an agar-based food model system containing iron(III)-oxide nanoparticles (IONP) were investigated. Agar samples containing IONPs at various concentrations (3, 6, 12 and 15mg per 100mL) were prepared to simulate the presence of ferric materials responsive to OMF. The samples were exposed to an external OMF (10mT, 10Hz) at -8°C for 24h. Higher supercooling probabilities were achieved in the IONP-containing samples, with probabilities of 75%, 75%, and 90% for the 3mg, 6mg, and 12mg concentrations, respectively. In contrast, lower supercooling probabilities of 60% and 55% were exhibited by the control samples (without nanoparticles) and samples containing zinc nanoparticles (ZNPs), respectively. It is suggested that the enhanced supercooling stability in IONPsamples is due to the interaction between the magnetic nanoparticles and the OMF, inhibiting ice nucleation possibly through the magneto-mechanical motion affecting water molecule orientation and hydrogen bonding networks.

Deep Supercooling of Li Salts By Trace Polymer Additives: An Approach to Single Li Ion Conducting Liquid Electrolytes

As a solution to global warming in recent years, the conversion from gasoline-powered vehicles to EVs is being attempted around the world, but the long charging time of the batteries in EVs has delayed their widespread adoption. For realizing the rapid charging of Li secondary batteries, also equipped with EVs, it is necessary to improve the transport properties of electrolytes such as ionic conductivity (σ) and Li+ transference number (t Li) 1. Therefore, all-solid-batteries with solid electrolytes, which has high σ and t Li ~ 1, are considered as a promising next-generation rechargeable battery, even though the designing of the electrolyte-electrode interface still remains a challenge 2. On the other hand, in liquid electrolytes (LEs), which has an advantage in interface design, t Li is still low. Although various studies have reported an enhancement of in LEs by means of changes to anion structures, the use of polyanions, and highly concentrated electrolytes, the reports of t Li ~ 1 are limited to the use of molten salts in a battery cell 3, 4. However, most of Li salt have both a high melting point and crystallinity, so that it crystallizes easily near room temperature, which is unsuitable for battery adaptation.To overcome this high crystallinity of Li salt at room temperature, we herein report anti-crystallization of Li salt by adding a small amount of polymers as obstacles to pack crystal structure. As shown in figure, we mixed lithium (fluorosulfonyl)(trifluoromethanesulfonyl)amide (Li[FTA]) and poly(methyl methacrylate) (PMMA) at the molar ratio of 9:1 (95.5 wt% of Li salt), thereby we could obtain the liquid mixture at room temperature. The result of differential scanning calorimetry shows that it remains supercooled state at ambient temperature (deep supercooling), even though 95 wt% of mixture is composed of Li salts. Additionally, the experimental value of 95.5 wt% Li[FTA]/ PMMA mixture was −25 °C and lower than that of Li[FTA] (−5.3 °C) and PMMA (106 °C), respectively (super-plasticizing). This indicates that the presence of slight polymer is not only an obstacle for packing into crystal lattice but also a plasticizer for Li salts. Therefore, this mixture, composed almost entirely of Li salt and liquified by deep supercooling and super-plasticizing effect, is considered as a deeply supercooled salt (DSS).DSS has ionic conduction at ambient temperature and show t Li ~ 1 under anion blocking conditions at 60 °C due to the absence of neutral solvents and only a small amount of polymer in electrolytes, which cannot cause valuable salt concentration gradients in measurement time scale. We will report ionic transport and electrochemical properties of DSS for batteries. Acknowledgement: This study was supported by the Advanced Low Carbon Technology Research and Development Program (ALCA-Next) of the Japan Science and Technology Agency (JST). Reference: 1. M. Diederichsen, E. J. McShane and B. D. McCloskey, ACS Energy Letters, 2017, 2, 2563-2575.2. Kato, S. Hori, T. Saito, K. Suzuki, M. Hirayama, A. Mitsui, M. Yonemura, H. Iba and R. Kanno, Nature Energy, 2016, 1, 16030.3. Kubota and H. Matsumoto, The Journal of Physical Chemistry C, 2013, 117, 18829-18836.4. Shigenobu, F. Philippi, S. Tsuzuki, H. Kokubo, K. Dokko, M. Watanabe and K. Ueno, Physical Chemistry Chemical Physics, 2023, 25, 6970-6978. Figure 1

The Cations Effect on Polymer-Assisted Anti-Crystallization of Alkali Metal Salts

To realize carbon neutrality, expanding the use of electric vehicles and stationary storage batteries for renewable energy is one of the effective procedures. The demand of rapid charging and discharging of Li-ion batteries continues to grow, but to achieve this, it is essential to improve Li+ transference number (t Li) of electrolytes as well as improving ionic conductivity (σ ion)1. Molten Li salts, consisted only of ions, do not cause concentration polarization, so that high Li+ transfer numbers (t Li ~ 1) have been reported under anion-blocking condition2. Although most Li salts have high melting point (T m > 100 °C) and are crystalline solids at room temperature, molten Li salt can facilitate formation of interface between electrode and electrolyte owing to the liquid state. Recently, the addition of a small amount of polymers was found to suppress crystallization and produce supercooled liquid (Li-Deeply Supercooled Salt, Li-DSS) that is stable for a long time at room temperature. Li-DSS achieved high t Li similar to the molten Li salts. In this study, DSSs were prepared with various alkali metal salts (Li, Na, K salts) and polymer to elucidate the effects of cationic and anionic structure on the formation of DSSs. The salts consisting of alkali metal cations and perfluoroamide anions such as (fluorosulfonyl)(trifluoromethansulfonyl)amide (FTA−) and bis (fluorosulfonyl)amide (FSA−), which have a relatively low melting point and low crystallinity, were selected. For polymer, we selected poly (methyl methacrylate) (PMMA), which is an amorphous polymer and has coordination sites with alkali metal cations. We could obtain Li-, Na-, and K-DSS with the addition of a small amounts of PMMA, but the stability (lifetime) of the supercooled state was in the order Li-, K-, Na-DSS, which did not follow the order of the ionic radius. The effects of cation on the thermal properties and ionic conductivity were also discussed. Acknowledgement This study was supported by the Advanced Low Carbon Technology Research and Development Program (ALCA-Next) of the Japan Science and Technology Agency (JST). References M. Diederichsen, E. J. McShane and B. D. McCloskey, ACS Energy Letters, 2017, 2, 2563-2575.Kubota and H. Matsumoto, The Journal of Physical Chemistry C, 2013, 117, 18829-18836.

Eutectic binary phase diagram and kinetically stable homogeneous co-amorphous mixtures of two imidazole drugs

Amorphous multicomponent formulations allow improving the solubility and thus the bioavailability of active pharmaceutical ingredients (APIs) that are poorly soluble in water, provided that the molecular mobility in such formulations does not promote crystallization in the amorphous (glassy) state during their shelf life. Multicomponent formulations may involve a single API mixed with excipients, but also two mutually compatible APIs. Here, we describe kinetically stable amorphous binary mixtures of two commercial antifungal imidazole APIs, bifonazole and clotrimazole, which have similar melting points and glass transition temperatures. The equilibrium phase diagram of this binary system, as determined by differential scanning calorimetry, follows the Schroeder-van Laar-LeChatelier predictions, as typically found for compounds that are miscible as liquids but immiscible in the crystalline form, and is characterized by an experimental eutectic composition close to equimolar composition (xbifonazole = 0.45) and eutectic melting point Te = 392 K. The glass transition temperature Tg varies linearly with composition, as found in ideal liquid mixtures. Dielectric spectroscopy characterization is carried out to investigate the relaxation dynamics of each amorphous API separately, and of the amorphous mixtures (both in the supercooled liquid and glass state). A single structural α relaxation is observed in all supercooled liquid mixtures, confirming their homogeneity. Both pure amorphous APIs display conformational secondary relaxations: the one of bifonazole stems from the torsional rotation of the imidazole ring; the one of clotrimazole is significantly slower than that of bifonazole, and is related to small-angle librations of the imidazole and chlorobenzene rings. Conformational relaxation processes are observed also in binary mixtures, which display also a Johari-Goldstein relaxation as pure clotrimazole. Despite the presence of both primary and secondary relaxations, the binary mixtures are observed to remain amorphous for at least twelve months both at Tg and slightly above it.

Clarifying the formation of equiaxed grains and microstructural refinement in the additive manufacturing of Ti-Cu

Controlling microstructural evolution in metallic additive manufacturing (AM) is difficult, especially in producing refined as-built grains instead of coarse, directional grains. Traditional solutions involve adding inoculants to AM feedstocks, but titanium (Ti) alloys cannot employ this approach without producing detrimental secondary phases. Ti-Cu (Ti-copper) alloys offer a solution through constitutional supercooling and/or solid state thermal cycling under AM conditions. This work analyzes a compositionally graded directed energy deposition (DED) Ti-Cu build, single-melt laser tracks, and dilatometric heat treatments to evaluate if, when, and by what mechanism(s) microstructural refinement occurs. Refinement by inoculation of unmelted powder particles was also considered. Constitutional supercooling produced no net microstructural refinement as any equiaxed dendrites which form are remelted with new deposition. This finding agreed with solidification modeling of powder bed fusion-laser beam (PBF-LB) and DED builds. Solid state thermal cycling refined microstructures only during ex-situ dilatometric heat treatments, suggesting build parameter optimization is needed to achieve refinement in-situ. Accidental heterogeneous nucleation on unmelted Ti powder, originating from the different thermophysical properties of Ti and Cu, provided the most significant microstructural refinement. This work systematically assesses the microstructural refinement mechanisms of Ti-Cu in AM builds and offers insights into microstructural control in eutectoid alloys.

Supercooled Water Droplets Impacting at High Speed on Superhydrophobic Surfaces: Open Questions Related to Icephobicity

It is posited that impact ice adhesion strength on superhydrophobic surfaces is related to droplet impalement. Several gaps still exist in the understanding of how different types of textured surfaces resist the impalement of high‐speed impacting droplets (<102 μm diameter at 102–103 m s−1). A previous study reveals that a pressure balance calculation can predict the wetting state of an impacting drop (≈103 μm diameter at ≈101 m s−1). However, the ability of this model to predict the wetting state of small droplets impacting at high speed or of droplets in a supercooled state has not been reported. To better understand supercooled microdroplet impalement, and to verify the hypothesis that droplet impalement is directly related to ice adhesion strength, herein, the impact behavior of microdroplets in a cold airflow onto surfaces of varying topography and wettability in an icing wind tunnel with support of high‐speed video images are investigated. Although the results do not allow for validating the above hypothesis about impalements and ice adhesion, they show that the difference between supercooled droplet spreading and retraction can be a predictor of ice adhesion strength. However, this relation must be validated with a greater body of data from samples with very diverse surface properties.

Correlative activation free energy (CAFE) model: Application to viscous processes in inorganic oxide glass-formers

We explore the concept of correlative activation free energy (CAFE) for the analysis and interpretation of viscosity data of a collection of 847 inorganic oxide glass formers that exhibit various degrees of non-Arrhenius behavior. The CAFE model formalism is strictly based on transition state theory and accounts for the variation in the activation barrier height for the viscous dissipation due to the structural evolution the system undergoes upon traversing the glass transition regime. Thus, fitting parameters are meaningful in a statistical thermodynamic context. Compared to the VFT and MYEGA equations, fits using the CAFE model are more robust when extrapolating to infinite temperature because the latter encodes non-enthalpic contributions to the rate coefficient more realistically. The CAFE model-based analysis reveals a strong connection between melt fragility and the degree of change in the potential energy landscape with temperature. Accordingly, while the average ground-state potential energy of the glass forming liquid gradually increases with temperature, the energy of the activated state remains relatively invariant. Our analysis also allows one to estimate the number of atoms involved in the viscous relaxation process, which ranges from approximately 10 to 50 atoms for the oxide glass formers studied. We observe that thermally activated dynamic phenomena exhibited by glassy networks, such as the mixed alkali effect, persist into the supercooled liquid state.

Excess Entropy of Metallic Glasses and Its Relation to the Glass-Forming Ability of Maternal Melts

The excess entropy ΔS with respect to the maternal crystal state has been determined from calorimetric data for 30 metallic glasses. It has been shown that the excess entropy in the supercooled liquid state ΔSsql is a universal characteristic of a glass independent of its thermal treatment. Six parameters often used to estimate the glass-forming ability of supercooled melts have been calculated for the same metallic glasses. It has been shown that all six parameters increase with ΔSsql and the glass-forming ability of supercooled melts increases with their structural disorder. A possible mechanism to implement this relation has been discussed.

Understanding the relationship between structural and dynamic properties in binary Mg-Al metallic liquids from molecular dynamics simulations

The structure and dynamics of the Mg-Al alloy for the different compositions were investigated using the embedded atom method (EAM) of molecular dynamics modeling. The results found that the icosahedral-like, mixed, and crystal-like increases with the temperature during the cooling process. When the temperature reaches the glass transition temperature (Tg) the last two types of clusters decrease with the temperature. The temperature Tg was determined using the Wendt-Abraham parameter, which found that it increases with increases in the fraction of Al. Investigations also revealed that the activation energy (Ea) decreases at higher temperatures and increases at temperatures below Tg. Additionally, viscosity was computed using the Vogel–Fulcher–Tammann (VFT) equation, showing a decrease in temperature in the supercooled liquid state. Moreover, an increase in the fraction of Al resulted in reduced fragility of the liquids.

Temperature dependence of spatial nanoheterogeneities of shear modulus in supercooled glycerol.

The boson peak in the terahertz vibrational spectrum carries information about nano-heterogeneities in the shear modulus in glass formers. Its evolution upon heating or cooling in a supercooled liquid state may shed light on the temperature dependence of heterogeneities. For this purpose, an analysis of the light scattering spectra of supercooled glycerol in the spectral range of the boson peak and fast relaxation was carried out and the parameters of the boson peak in the temperature range 180-330K were determined. The temperature dependent frequency of the boson peak was then expressed in terms of the mean-square amplitude of the shear modulus fluctuations. This was done using the heterogeneous elasticity theory in combination with the perturbation theory on small fluctuations and Ioffe-Regel criterion for transverse vibrations in glass formers. The contribution of structural relaxation effects to phonon damping becomes significant with increasing temperature. It is shown here that structural relaxation largely determines the temperature dependence of the mean-square fluctuations of the shear modulus at high temperatures. By solving the inverse problem, the temperature dependence of shear modulus fluctuations was obtained. It shows a rapid decrease above ∼250K with a linear extrapolation going to zero at the so-called Arrhenius temperature TA = 350K. Comparison with literature data on the Landau-Placzek ratio shows that they have a similar temperature dependence at T < TA, which is explained by the appearance of nanometer scale spatial heterogeneities below TA. This is confirmed by the temperature dependence of the amplitude of the boson peak.

Formation of Self-Healing Granular Eutectogels through Jammed Carbopol Microgels in Supercooled Deep Eutectic Solvent.

Typically, gel-like materials consist of a polymer network structure in a solvent. In this work, a gel-like material is developed in a deep eutectic solvent (DES) without the presence of a polymer network, achieved simply by adding microgels. The DES is composed of choline chloride and citric acid and remains stably in a supercooled state at room temperature, exhibiting Newtonian fluid behavior with high viscosity. When the microgel (Carbopol) concentration exceeds 2 wt %, the DES undergoes a transition from a liquid to a soft gel state, characterized as a granular eutectogel. The soft gel characteristics of eutectogels exhibit a yield stress, and their storage moduli exceed the loss moduli. The yield stress and storage moduli are observed to increase with increasing microgel concentration. In contrast, the ion conductivity decreases with increasing microgel concentration but eventually levels off. Because the eutectogel can dissolve completely in excess water, it is a physical gel-like material, attributed to the densely packed structure of microgels in the supercooled DES. Due to the absence of networks, the granular eutectogel has the capability to self-heal simply by being pushed together after being cut into two pieces.

Study on effects of anti-freeze protein and polyvinyl alcohol on the production and flow behavior of ice slurry

Ice slurry is a promising functional fluid with high thermal energy density and high heat transfer rate. However, the agglomeration of the ice particles in flowing ice slurry can cause blocking of tubes. In this study, anti-freeze protein (AFP) and polyvinyl alcohol (PVA) were selected as additives to prevent the agglomeration of ice particles in ice slurry. Ice slurry was generated using the release of the supercooled state of 3 mass% NaCl solution containing the additives. The size of the ice particles in the ice slurry was observed, and the average area of the ice particles was evaluated to reveal the effects of the additives on the ice particle size. Furthermore, the flow behavior of the ice slurry in a tube was observed, and the effects of the additives on the flow behavior and prevention of the agglomeration of the ice particles were evaluated experimentally. It was found that the average area decreased with increasing concentration of the additives, and the effect of AFP on the average area was particularly significant. In the case of without the additives, the ice particles flowed in the tube while the ice particles agglomerated. On the other hand, the ice particles in the ice slurry with the additives flowed without agglomeration in the tube, especially in the case of AFP addition. It was found that AFP prevented the agglomeration of the ice particles in the ice slurry flow. Moreover, the ice slurries with AFP show the significant tendency for pseudo-plastic fluid.

Compressibility, diffusivity, and elasticity in relationship with ionic conduction: An atomic scale description of densified Li2S${\rm Li}_2{\rm S}$–SiS2${\rm SiS}_2$ glasses

AbstractWe examine the dynamic and ionic properties of a typical sulfide glass electrolyte 50–50 using molecular dynamics simulations and a previously parameterized force‐field able to describe both the crystalline phase and the corresponding glass. We especially focus on the effect of moderate pressures on the glassy and supercooled state since the design of all‐solid state batteries use molding conditions at moderate pressures in order to achieve contact between the electrolyte and the electrodes. The behavior of the conductivity with pressure permits to define an activation volume and to infer the role of compressibility and diffusivity, the latter contributing dominantly to ionic conduction, whereas temperature does not seem to impact the structural properties. These features are linked with the underlying dynamics of the Li ions as studied here by computing the longitudinal and transversal atomic species current correlations. The resulting elasticity is found to be close to experimental values.

Experimental analysis of freezing desalination using gravity and centrifugal methods with economic evaluation of coupled freezing desalination and ice storage system

This study conducted experiments to compare the desalination efficiency of gravity and centrifugal desalination methods for freezing desalination, showing the superiority of centrifugal desalination. Moreover, through experiments on supercooled water production, it was determined that supercooled water can operate stably at an evaporator temperature of −4.5 °C, and its supercooling state can be released using ultrasound. Based on the experimental results, a novel system that combines freezing desalination with ice storage is proposed. The proposed system utilizes supercooled water for ice production and centrifugal post-treatment, using desalinated ice as a cold storage medium to integrate desalination and ice storage. The proposed system showed a 30 % lower total capital cost compared to conventional systems, with a payback period of 38.18 % lower than conventional system (5.42 years). Additionally, the system demonstrated optimal economic performance when utilizing 80 % of its ice storage capacity, with a payback period of 3.38 years, contrasting with 7.62 years when utilizing 20 % storage capacity. The application of this system in four regions with varying peak and off-peak electricity prices, including Guangdong, Fujian, Hainan, and, France revealed that the system demonstrates greater economic viability in areas with significant disparities in electricity pricing.

Diffusion proxies reveal the dynamic process in supercooled and glassy lithium diborate

Understanding the effective diffusion coefficient (D) is crucial for describing atomic transport during crystal nucleation in supercooled liquids and glasses. However, pinpointing the key structural units driving crystallization in intricate, multicomponent glass-formers remains a challenge. This study presents a novel analysis of lithium diborate (Li₂O·2 B₂O₃ - LB₂) crystallization in supercooled and glassy states by using available viscosity and crystallization data for samples of the same batch. An original key feature is that the nucleation rates were measured using a single-stage rather than the traditional double-stage heat treatment. We compared three proxies for D: Dη obtained from viscosity, DU derived from crystal growth rates, and Dτ estimated from nucleation time-lags. Our analysis revealed that at deep supercoolings, below the glass transition temperature, DU and Dτ yield similar steady-state nucleation rate estimates, which significantly exceed those predicted by using Dη (the most frequently used diffusion proxy). This result suggests that the atomic jumps governing crystal nucleation may be comparable to those in crystal growth, but distinct from those associated with cooperative rearrangements controlling viscous flow. Additionally, the estimated kinetic spinodal temperature (Tks) is above the Kauzmann temperature Tk, implying that crystal nucleation precedes relaxation to the supercooled liquid state, circumventing the entropy paradox and corroborating recent MD simulations for other substances. These findings are valuable for refining theoretical models of crystal nucleation and highlight the complexities of the glassy state.

Supercooled erythritol for high-performance seasonal thermal energy storage

Seasonal storage of solar thermal energy through supercooled phase change materials (PCM) offers a promising solution for decarbonizing space and water heating in winter. Despite the high energy density and adaptability, natural PCMs often lack the necessary supercooling for stable, long-term storage. Leveraging erythritol, a sustainable mid-temperature PCM with high latent heat, we introduce a straightforward method to stabilize its supercooling by incorporating carrageenan (CG), a bio-derived food thickener. By improving the solid-liquid interfacial energy with the addition of CG the latent heat of erythritol can be effectively locked at a very low temperature. We show that the composite PCM can sustain an ultrastable supercooled state below −30 °C, which guarantees no accidental loss of the latent heat in severe cold regions on Earth. We further demonstrate that the common ultrasonication method can be used as the key to unlocking the latent heat stored in the CG-thickened erythritol, showing its great potential to serve as a high-performance, eco-friendly PCM for long-term seasonal solar energy storage.

Frost fighters: unveiling the potential of microbial antifreeze proteins in biotech innovation.

Polar environments pose extreme challenges for life due to low temperatures, limited water, high radiation, and frozen landscapes. Despite these harsh conditions, numerous macro and microorganisms have developed adaptive strategies to reduce the detrimental effects of extreme cold. A primary survival tactic involves avoiding or tolerating intra and extracellular freezing. Many organisms achieve this by maintaining a supercooled state by producing small organic compounds like sugars, glycerol, and amino acids, or through increasing solute concentration. Another approach is the synthesis of ice-binding proteins, specifically antifreeze proteins (AFPs), which hinder ice crystal growth below the melting point. This adaptation is crucial for preventing intracellular ice formation, which could be lethal, and ensuring the presence of liquid water around cells. AFPs have independently evolved in different species, exhibiting distinct thermal hysteresis and ice structuring properties. Beyond their ecological role, AFPs have garnered significant attention in biotechnology for potential applications in the food, agriculture, and pharmaceutical industries. This review aims to offer a thorough insight into the activity and impacts of AFPs on water, examining their significance in cold-adapted organisms, and exploring the diversity of microbial AFPs. Using a meta-analysis from cultivation-based and cultivation-independent data, we evaluate the correlation between AFP-producing microorganisms and cold environments. We also explore small and large-scale biotechnological applications of AFPs, providing a perspective for future research.

Theoretical and experimental analysis of sea ice centrifugal desalination and supercooled water production for slurry ice

This study presents a comprehensive investigation of centrifugal desalination of sea ice and the production of slurry ice from supercooled water. A mathematical model for centrifugal desalination was established and validated through experiments. The results displayed a high level of accuracy in both the theoretical and experimental analyses, with an average goodness of fit of approximately 0.94. An experimental platform is established to produce supercooled water, using different types of water as ice-making solutions. The slurry ice is more suitable for centrifugal desalination than solid ice, and it can be obtained by disrupting the supercooled state of supercooled water, with finer ice crystals produced through ultrasonic supercooling release compared to natural methods. Decreasing the refrigerant temperature benefits enhancing the supercooling degree while compromising the stability of supercooled water generation. The stability is investigated with variations in refrigerant temperature to generate a solution temperature 2.0 °C higher than the refrigerant. When the supercooling degree is 1.0 °C, all of these solutions have a high stability of 80 %, however, it becomes worse as the supercooling degree increases. At the supercooling degree of 2.0 °C, saltwater has the highest stability of only 35 %, and seawater has the lowest stability of 15% due to its complicated composition. This phenomenon also reveals that conducting experiments using saline solution instead of seawater can lead to significant misleading effects. Additionally, the impact of flow rate on the supercooling degree is investigated, showing a minor influence.

Multibubble sonoluminescence in supercooled water.

Cavitation in supercooled water has been induced by the short ultrasound pulses of an ultrasonic horn driven at 20kHz. The cavitation during the ultrasonic pulses and occasionally the crystallization events thereafter have been imaged by a high-speed camera. The probability of ice crystallization in dependence on the pulse duration and temperature showed a high chance for the water to remain liquid if sufficiently short bursts of moderate acoustic power were applied. This regime has been used for the assessment of sonoluminescence (SL) from the generated cavitation bubbles in the supercooled liquid state. To this end, light emitting events were summed up over a number of ultrasonic pulses by an image intensifier. SL appeared mostly directly under the tip of the ultrasonic horn and sometimes also a few millimeters below the tip. The intensity of SL events showed a slight rise for a decrease in temperature, i.e., for an increase in supercooling. This behavior is in accord with the SL dependence on temperature above the freezing point and might be attributed to a further lowering of vapor pressure. An increase in the bubble collapse peak temperature for increased supercooling is calculated on the basis of spherical bubble model calculations, which supports the findings. The simulations predict further that the peak temperature will fall off again beyond a certain supercooling level.