Anti-crystallization light molecule solution with super-wide supercooling window and preparation method thereof

Abstract

This invention relates to an anti-crystallization light molecular solution with an ultrawide supercooling window and its preparation method. The method first involves heating a mixture of a low-molecular-weight polyol and a quaternary ammonium salt to obtain a deep eutectic solvent, which is then uniformly mixed with water. This invention constructs a "competitive hydrogen bond network" composed of the polyol, quaternary ammonium salt, and water, and utilizes the nuclear quantum tunneling effect at low temperatures to synergistically suppress the ordered crystallization of water molecules. The resulting anti-crystallization light molecular solution has a glass transition temperature as low as -130°C, maintains a stable liquid state over an ultrawide temperature range, and possesses low viscosity, high fluidity, and good conductivity, making it widely applicable as a cryogenic functional medium in polar, deep-sea, and aerospace fields.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor manufacturing processes, and particularly relates to an anti-crystallization light molecule solution with an ultrawide supercooling window and its preparation method. Background Technology

[0002] In extreme low-temperature environments such as polar regions, deep seas, and aerospace applications, functional media capable of maintaining a stable liquid state at low temperatures are required. These include antifreeze coolants, cryogenic heat transfer media, cryogenic electrolytes / conductive fluids, cryogenic sensing media, and cryogenic lubricants and sealing media. If these media crystallize or undergo phase separation at low temperatures, it often leads to a sharp decrease in fluidity, a decline in electrical / thermal conductivity, volume expansion causing structural damage, and even device failure. Therefore, developing "deep supercooled anti-crystallization liquids" that can suppress crystallization, maintain a metastable liquid state, and possess adjustable functionality within extremely low temperature ranges has significant scientific and engineering application value.

[0003] In recent years, water-based multi-solute deep supercooling antifreeze systems (such as those containing Al) have been developing rapidly. 3+ Ca 2+ Li + Na + K + Zn 2+ Plasma salt solutions and their co-solvent complexes have attracted widespread attention. These systems mainly rely on strong electrostatic / coordination interactions between high-charge-density metal cations and water molecules to suppress ice crystal formation, representing a typical "heavy ion-strong interaction" antifreeze strategy.

[0004] However, under this design approach, which uses entropy change in hydrogen bond networks as the core control method, the improvement of liquid stability of the system under extreme low-temperature conditions (such as below approximately -80°C) has reached a bottleneck. Although some studies have introduced structural order parameters (such as microscopic tetrahedral entropy S) to improve the system's stability, this approach has not yet been fully realized. Qtet This study aims to establish a structure-activity relationship between ionic properties and antifreeze performance, and thereby optimize formulations. However, the glass transition temperature (Tg) of multi-solute systems reported to date remains a challenge. g The lowest temperature it can reach is still only about -117.1℃, which is difficult to meet the application requirements of deeper temperature ranges (such as below -150℃).

[0005] Therefore, developing a class of lightweight anti-crystallization liquids that do not rely on strong coordination of heavy ions, can achieve deep supercooling in a wider temperature range, and possess both good low-temperature stability and practicality, along with corresponding preparation methods, has become a key direction that urgently needs to be broken through in this field. Summary of the Invention

[0006] The technical problems solved by this invention are: 1. Existing deep supercooled anti-crystallization liquid systems (such as the H2O–salt system) generally suffer from limited low-temperature liquid stability, high crystallization initiation temperature, narrow supercooling window, and dependence on strong interactions (such as strong coordination between high-ionic-potential metal cations and water), making it difficult to maintain a stable liquid state under extreme cryogenic conditions. 2. Existing systems are prone to salt precipitation and phase separation at low temperatures, affecting their application stability and reliability.

[0007] In view of the technical problems existing in the prior art, the present invention designs an anti-crystallization light molecule solution with an ultrawide supercooling window and a method for preparing the same.

[0008] It should be noted that, in this invention, unless otherwise specified, the specific meaning of "comprising" in relation to composition definition and description includes both open-ended meanings such as "comprising," "including," etc., and closed-ended meanings such as "composed of," etc., and similar meanings.

[0009] To solve the aforementioned technical problems, the present invention adopts the following solution:

[0010] A method for preparing an anti-crystallization light molecule solution with an ultrawide supercooling window includes the following steps:

[0011] Step 1: Mix low molecular weight polyols and quaternary ammonium salts under heating conditions to synthesize deep eutectic solvent prepolymers;

[0012] Step 2: Mix the deep eutectic solvent prepolymer synthesized in Step 1 with water to obtain the anti-crystallization light molecule solution with an ultrawide supercooling window.

[0013] Furthermore, in step 1, the molar ratio of low molecular weight polyol to quaternary ammonium salt is 7-10:1; the heating conditions are a reaction temperature of 40-80℃, a reaction time of 1-3 hours, the reaction is carried out under magnetic stirring, and the reaction environment is an inert gas environment.

[0014] Further, in step 2, the deep eutectic solvent prepolymer synthesized in step 1 is cooled to room temperature, and water is slowly added in proportion under continuous stirring; the water content is 0.1-0.9 of the total molar amount of the anti-crystallization light molecule solution with an ultra-wide supercooling window.

[0015] Furthermore, the low molecular weight polyol mentioned in step 1 is a polyol with 2 to 6 carbon atoms.

[0016] Further, the low molecular weight polyol is one of ethylene glycol, 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, glycerol (glycerol), 1,2,4-butanetriol, 1,2,6-hexanetriol, 1,2,3-propanetriol, pentaerythritol, diethylene glycol, triethylene glycol, methyl propylene glycol (2-methyl-1,3-propanediol), or ethyl ethylene glycol (2-ethyl-1,3-propanediol).

[0017] Furthermore, the quaternary ammonium salt component mentioned in step 1 has the general formula R. 1 R 2 R 3 R 4 N + X - ,

[0018] Among them, R 1 R 2 R 3 R 4 It is either hydrogen or C1-C4 alkyl, and not both hydrogen at the same time;

[0019] X- represents a halide ion, carboxylate ion, hydrogen sulfate ion, or nitrate ion.

[0020] Furthermore, the water used in step 2 is deionized water, ultrapure water, or reverse osmosis water.

[0021] The present invention also discloses an anti-crystallization light molecule solution with an ultrawide supercooling window, which is prepared according to the above preparation method.

[0022] Furthermore, its glass transition temperature is below -130°C, and it remains liquid and does not crystallize below -120°C.

[0023] The present invention also discloses the use of the above-mentioned anti-crystallization light molecule solution with an ultra-wide supercooling window in low-temperature heat transfer media, low-temperature electrolytes, low-temperature sensing media or low-temperature lubrication and sealing media.

[0024] This invention provides a solution for use as a cryogenic lubrication and sealing medium, primarily applied to the joint bearings of lunar rover or ultra-low cryogenic mechanical equipment. In extreme environments as low as -120°C, its ultra-wide supercooling window maintains its liquid fluidity, effectively lubricating moving parts, reducing wear, maintaining the elasticity and tightness of seals, preventing media leakage and external contamination, and ensuring long-term reliable operation of mechanical systems at deep cryogenic temperatures.

[0025] In step 1 of this invention, the low molecular weight polyol can be further preferably ethylene glycol, 1,2-propanediol, 1,2-hexanediol, and glycerol. The reaction temperature can preferably be 40-60°C; the reaction time can preferably be 1-2 hours.

[0026] There is no particular limitation on the magnetic stirring speed, the goal is to promote the full occurrence of the reaction. Generally, the magnetic stirring speed is preferably 300-800 rpm, more preferably 400-600 rpm.

[0027] In this invention, there are no special restrictions on the inert gas; it can be nitrogen, argon, helium, etc.

[0028] In step 1 of this invention, the reactants are placed in a heatable and stirred reaction vessel, and the temperature is controlled within a suitable range. A magnetic stirrer is used to react until a homogeneous, transparent, viscous liquid deep eutectic solvent (DES) prepolymer is formed. Step 1 aims to facilitate the reaction of the hydroxyl groups of the polyol with the anions (such as Cl-) in the quaternary ammonium salt. - Hydrogen bonding between the two components allows for the construction of the initial hydrogen bond acceptor-donor complex structure.

[0029] In step 2 of the present invention, the water content is preferably 0.2-0.7% of the total molar amount of the anti-crystallization light molecule solution with an ultra-wide supercooling window.

[0030] In step 2 of this invention, the system temperature can be precisely controlled by a water bath during the water addition process. Stirring continues under certain temperature and speed conditions until a clear, homogeneous and stable ternary solution is obtained. The ternary solution is the anti-crystallization light molecule solution with an ultrawide supercooling window.

[0031] In this step, the introduction of water further activates the dynamic recombination process of hydrogen bonds in the system, promoting the formation of a "competitive hydrogen bond network" among polyol-quaternary ammonium salt-water (EG-ChCl-H2O). This network effectively inhibits the orderly stacking of water molecules at the molecular scale.

[0032] In this invention, according to the above-mentioned quaternary ammonium salt general formula R 1 R 2 R 3 R 4 N + X - It can be determined that it can be choline chloride (2-hydroxyethyltrimethylammonium chloride), acetylcholine (2-hydroxyethyltrimethylammonium acetate), choline bromide (2-hydroxyethyltrimethylammonium bromide), tetramethylammonium chloride, tetramethylammonium acetate, tetraethylammonium chloride, tetraethylammonium bromide, trimethylethylammonium chloride, triethylmethylammonium acetate, formate choline (2-hydroxyethyltrimethylformate), (2-methoxyethyl)trimethylammonium chloride, or (1-hydroxypropyl)trimethylammonium chloride.

[0033] In this invention, the preferred materials are choline chloride, acetylcholine, choline bromide, and tetramethylamine chloride.

[0034] The water (H2O) used in this invention is ultrapure water with a resistivity of not less than 18.2 MΩ·cm (25℃), which meets the technical requirements of EW-I grade in the national standard GB / T11446.1-2013.

[0035] The purpose of using this high-purity water is to minimize electrolyte impurities (such as sodium) in the water. + K + Cl - The interference and disruption of the precise hydrogen bond network in the system by (etc.) ensures that the "competitive hydrogen bond network" constructed by low molecular weight polyols and quaternary ammonium salts can achieve its optimal kinetic and thermodynamic stability, thereby guaranteeing the ultrawide supercooling window of the solution under extreme cryogenic conditions.

[0036] In this invention, deionized water or reverse osmosis water of equivalent purity can also be used as a substitute.

[0037] In this invention, the mechanism and working principle of constructing a dynamic "competitive hydrogen bond network" are as follows:

[0038] Firstly, a light molecular system: using low molecular weight polyols as hydrogen bond donors (HBD) and specific quaternary ammonium salts as hydrogen bond acceptors (HBA), a ternary light molecular solution system is constructed with water.

[0039] By regulating the molecular structure and ratio of polyols / quaternary ammonium salts and precisely controlling the water content, a dynamic and disordered "competitive hydrogen bond network" is constructed in the system.

[0040] This network can effectively interfere with the orderly arrangement of water molecules, thereby significantly widening the supercooling window to below -130.47℃ while maintaining the low viscosity and high fluidity of the solution. This achieves a fundamental shift in the anti-crystallization mechanism from "strong electrostatic coordination" to "dynamic hydrogen bond regulation of light molecules", forming a deep supercooled anti-crystallization liquid with an ultra-wide supercooling window.

[0041] Secondly, nuclear quantum tunneling: This system exhibits significant nuclear quantum effects under low-temperature conditions (< -120℃), specifically manifested in the proton (H) + Tunneling migration occurs in dynamic hydrogen bond networks via the Grothuss skipping mechanism.

[0042] This quantum behavior allows the hydrogen bond network to maintain a certain dynamics and reconfiguration capability at extremely low temperatures, thereby effectively suppressing the process of water molecules arranging into the lattice for ordering and enhancing the metastable stability of the deep supercooled liquid state.

[0043] This invention provides a method for preparing an anti-crystallization light molecule solution with an ultrawide supercooling window, which has the following beneficial effects:

[0044] 1. This invention constructs a dynamic "competitive hydrogen bond network" in solution by precisely controlling the ratio of low-molecular-weight polyols, specific quaternary ammonium salts, and water. This network competitively binds water molecules, effectively disrupting their ordered arrangement and ice crystal nucleation process, thereby significantly widening the supercooling window of the solution thermodynamically. This invention also cleverly utilizes the nuclear quantum tunneling effect exhibited by light molecular systems at deep cryogenic temperatures (manifested as protons jumping through the hydrogen bond network via the Grotthuss mechanism). This quantum behavior endows the network with the ability to maintain dynamic reconstruction even at extreme low temperatures, thus further stabilizing the deep supercooled liquid state kinetically and inhibiting crystallization. Finally, through the synergistic mechanism of "classical hydrogen bond competition" and "quantum proton jumping," this invention achieves an ultrawide supercooling window (extendable to below -130°C) that is difficult to achieve with traditional "heavy ion-strong coordination" systems using only lightweight, low-viscosity conventional components, while the solution also possesses excellent fluidity, stability, and ease of preparation.

[0045] 2. The anti-crystallization light molecule solution with an ultra-wide supercooling window prepared by this invention has a wide range of components and is flexible in design.

[0046] 3. This invention provides a set of universal design rules. By selecting different molecular characteristics and proportion ranges of hydrogen bond donors (polyols), acceptors (quaternary ammonium salts), and solvents (water, etc.), it provides solid patent protection for developing a series of products based on the same core mechanism and broadens the space for material selection and performance regulation. Attached Figure Description

[0047] Figure 1 : Differential scanning calorimetry characterization of the anti-crystallization light molecule solution of Example 1 at an appropriate water content;

[0048] Figure 2 Differential scanning calorimetry characterization of the anti-crystallization light molecule solution in Example 1 at high water content;

[0049] Figure 3 : Differential scanning calorimetry characterization of the deep eutectic solution of Comparative Example 1 at different molar ratios;

[0050] Figure 4 : This is the temperature-varying in-situ infrared spectrum of the anti-crystallization light molecule solution of Example 1;

[0051] Figure 5 : Viscosity-temperature dependence curve of the anti-crystallization light molecule solution in Example 1;

[0052] Figure 6: This is a temperature-varying broadband dielectric diagram-structural relaxation characterization diagram of the anti-crystallization light molecule solution in Example 1;

[0053] Figure 7 : This is a temperature-varying broadband dielectric diagram-conductivity relaxation characterization diagram of the anti-crystallization light molecule solution in Example 1;

[0054] Figure 8 : This is the temperature-dependent dielectric plot-conductivity curve of the anti-crystallization light molecule solution in Example 1.

[0055] Figure 9 : This is a temperature dependence diagram of the proton jumping activation energy of the anti-crystallization light molecule solution in Example 1; Detailed Implementation

[0056] The present invention will be further described below with reference to specific embodiments and accompanying drawings:

[0057] The present invention does not have any particular limitation on the source of the low molecular weight polyol component, which can be commercially available or prepared according to methods known to those skilled in the art.

[0058] The present invention does not have any particular limitation on the source of quaternary ammonium salts, which can be commercially available or prepared according to methods known to those skilled in the art.

[0059] Example 1:

[0060] Step 1: Accurately weigh ethylene glycol (12.40 g, 0.2 mol) and choline chloride (2.79 g, 0.02 mol) at a molar ratio of 10:1. Place both in a 100 mL three-necked flask equipped with a magnetic stir bar. Place the flask in an oil bath, heat to 60 °C and maintain a constant temperature, stirring continuously at 400 rpm for 100 minutes. After the reaction is complete, a homogeneous, transparent, viscous deep eutectic solvent (DES) prepolymer is obtained, denoted as solution A.

[0061] Step 2: Cool the above solution A to 25°C (room temperature). While maintaining a stirring rate of 400 rpm, use a constant-pressure dropping funnel to slowly add the corresponding masses of ultrapure water (as listed in the table below) to 17 equal portions of solution A, each containing 15.19 g (0.22 mol). Control the dropping rate to approximately 1 mL / min, ensuring the system temperature is maintained at 25 ± 2°C via a water bath. After the water is added, continue stirring at 25°C and 400 rpm for 30 minutes until a clear, homogeneous ternary solution without visible phase separation is obtained—that is, a light molecule solution with an ultrawide supercooling window that resists crystallization. The resulting samples are designated as S1-a to S1-q.

[0062] Table 1

[0063] Example 2:

[0064] Step 1: Accurately weigh 18.42 g (0.2 mol) of glycerol and choline chloride (2.79 g, 0.02 mol) at a molar ratio of 10:1. Place both in a 100 mL three-necked flask equipped with a magnetic stirrer. Place the flask in an oil bath, heat to 50 °C and maintain a constant temperature, stirring continuously at 500 rpm for 2 hours. After the reaction is complete, a homogeneous, transparent, viscous deep eutectic solvent (DES) prepolymer is obtained, denoted as solution B.

[0065] Step 2: Cool the above solution B to 25°C (room temperature). While maintaining a stirring rate of 500 rpm, use a constant-pressure dropping funnel to slowly add the corresponding masses of ultrapure water (as listed in the table below) to 17 equal portions of solution B, each weighing 21.21 g (0.22 mol). Control the dropping rate to approximately 1 mL / min, ensuring the system temperature is maintained at 25 ± 2°C via a water bath. After the water is added, continue stirring at 25°C and 500 rpm for 30 minutes until a clear, homogeneous ternary solution with an ultrawide supercooling window and resistance to crystallization (light molecular weight) is obtained. The resulting samples are designated as T1-a to T1-q.

[0066] Table 2

[0067] Example 3:

[0068] Step 1: Accurately weigh ethylene glycol (9.92 g, 0.16 mol) and choline bromide (3.68 g, 0.02 mol) at a molar ratio of 8:1. Place both in a 100 mL three-necked flask equipped with a magnetic stir bar. Place the flask in an oil bath, heat to 40°C and maintain a constant temperature, stirring continuously at 600 rpm for 1 hour. After the reaction is complete, a homogeneous, transparent, viscous deep eutectic solvent (DES) prepolymer is obtained, denoted as solution C.

[0069] Step 2: Cool the above solution C to 25°C (room temperature). While maintaining a stirring rate of 600 rpm, use a constant-pressure dropping funnel to slowly add the corresponding masses of ultrapure water (as listed in the table below) to 17 equal portions of solution C, each containing 13.60 g (0.18 mol). Control the dropping rate to approximately 1 mL / min, ensuring the system temperature is maintained at 25 ± 2°C via a water bath. After the water is added, continue stirring at 25°C and 600 rpm for 30 minutes until a clear, homogeneous ternary solution with an ultrawide supercooling window and resistance to crystallization (light molecular weight) is obtained. The resulting samples are designated as U1-a to U1-q.

[0070] Table 3

[0071] Example 4:

[0072] Step 1: Accurately weigh glycerol (19.34 g, 0.21 mol) and choline bromide (4.64 g, 0.03 mol) at a molar ratio of 7:1. Place both in a 100 mL three-necked flask equipped with a magnetic stir bar. Place the flask in an oil bath, heat to 80°C and maintain a constant temperature, stirring continuously at 500 rpm for 70 minutes. After the reaction is complete, a homogeneous, transparent, viscous deep eutectic solvent (DES) prepolymer is obtained, denoted as solution D.

[0073] Step 2: Cool the above solution D to 25°C (room temperature). While maintaining a stirring rate of 500 rpm, use a constant-pressure dropping funnel to slowly add the corresponding masses of ultrapure water (as listed in the table below) to 17 equal portions of solution D, each with a mass of 23.98 g (0.24 mol). Control the dropping rate to approximately 1 mL / min, ensuring the system temperature is maintained at 25 ± 2°C via a water bath. After the water is added, continue stirring at 25°C and 500 rpm for 30 minutes until a clear, homogeneous ternary solution with an ultrawide supercooling window and resistance to crystallization (light molecular weight) is obtained. The resulting samples are designated V1-a to V1-q.

[0074] Table 4

[0075] Example 5:

[0076] Step 1: Accurately weigh 1,2-propanediol (13.697 g, 0.18 mol) and acetylcholine (3.264 g, 0.02 mol) in a molar ratio of 9:1. Place both in a 100 mL three-necked flask equipped with a magnetic stir bar. Place the flask in an oil bath, heat to 80°C and maintain a constant temperature, stirring continuously at 500 rpm for 70 minutes. After the reaction is complete, a homogeneous, transparent, viscous deep eutectic solvent (DES) prepolymer is obtained, denoted as solution E.

[0077] Step 2: Cool the above solution E to 25°C (room temperature). While maintaining a stirring rate of 500 rpm, use a constant-pressure dropping funnel to slowly add the corresponding masses of ultrapure water (as listed in the table below) to 17 equal volumes of solution E, each containing 16.961 g (0.20 mol). Control the dropping rate to approximately 1 mL / min, ensuring the system temperature is maintained at 25 ± 2°C via a water bath. After the water is added, continue stirring at 25°C and 500 rpm for 30 minutes until a clear, homogeneous ternary solution with an ultrawide supercooling window and resistance to crystallization (light molecular weight) is obtained. The resulting samples are designated W1-a to W1-q.

[0078] Table 5

[0079] Example 6:

[0080] Step 1: Accurately weigh 1,2-hexanediol (18.027 g, 0.2 mol) and tetramethylamine chloride (2.192 g, 0.02 mol) at a molar ratio of 10:1. Place both in a 100 mL three-necked flask equipped with a magnetic stir bar. Place the flask in an oil bath, heat to 80°C and maintain a constant temperature, stirring continuously at 500 rpm for 70 minutes. After the reaction is complete, a homogeneous, transparent, viscous deep eutectic solvent (DES) prepolymer is obtained, denoted as solution F.

[0081] Step 2: Cool the above solution F to 25°C (room temperature). While maintaining a stirring rate of 500 rpm, use a constant-pressure dropping funnel to slowly add the corresponding masses of ultrapure water (as listed in the table below) to 17 equal portions of solution F, each with a mass of 20.219 g (0.22 mol). Control the dropping rate to approximately 1 mL / min, ensuring the system temperature is maintained at 25 ± 2°C via a water bath. After the water is added, continue stirring at 25°C and 500 rpm for 30 minutes until a clear, homogeneous ternary solution with an ultrawide supercooling window and resistance to crystallization (light molecular weight) is obtained. The resulting samples are designated as X1-a to X1-q.

[0082] Table 6

[0083] Comparative Examples 1-2:

[0084] Except for the absence of water in step 2, all other operations remained unchanged, and Examples 1 and 2 were repeated to obtain Comparative Example 1 and Comparative Example 2 in sequence. The resulting solutions were named E1, E2, E3, and E4 in sequence.

[0085] The crystallization temperature, glass transition temperature, viscosity, and conductivity of the deep eutectic solution and the anti-crystallization light molecule solution were determined by the following test methods, and the results are shown in Table 7.

[0086] Table 7:

[0087] As can be seen from Examples 1 and 2, no crystallization / melting phase transition temperature occurred during the low-temperature freezing process, which is indicated by the symbol "-".

[0088] Both Example 1 and Example 2 only showed low glass transition temperatures. The glass transition temperature of Example 1 was as low as -130.47℃, and the glass transition temperature of Example 2 was as low as -125.3℃.

[0089] Comparative Examples 1 and 2 exhibited crystallization / melting phase transitions at relatively high temperatures during the cryogenic freezing process. The melting temperature of Comparative Example 1 was -54.7℃, and the melting temperature of Comparative Example 2 was -80℃. Neither Comparative Example 1 nor Comparative Example 2 exhibited a glass transition temperature, which is indicated by the symbol "-".

[0090] Regarding the product performance of Examples 2-6:

[0091] The light molecular solutions prepared in Examples 2-6 all exhibit excellent anti-crystallization properties and ultra-low supercooling ability at low temperatures, maintaining a liquid state within a temperature range of approximately -120°C. In Examples 2, 3, 4, 5, and 6, the anti-crystallization ability initially increases and then decreases with increasing water content. Within a suitable water content range, they exhibit ultra-low supercooling ability; however, at very high water content, a crystallization / melting phase transition occurs.

[0092] Performance testing methods:

[0093] Property 1 crystallization temperature and Property 2 glass transition temperature:

[0094] Characterization was performed using differential scanning calorimetry (DSC). 5–15 mg of sample was sealed in an aluminum crucible and cooled to -150 °C at a rate of 5 °C / min under a nitrogen atmosphere, then held at that temperature for 5 min to eliminate thermal history. The temperature was then increased to 25 °C at a rate of 5 °C / min, and the heat flow curve was recorded. The onset point was determined by extrapolating the change in specific heat capacity from this curve. g If crystallization is present, its melting temperature Tf can be determined by the endothermic peak during the heating process.

[0095] Performance 3 Viscosity:

[0096] The test was conducted using a rotational rheometer equipped with a liquid nitrogen cooling system (such as the Anton Paar MCR series). A parallel plate clamp was used. Before measurement, the sample was thoroughly stirred. Using a pre-cooled pipette, 0.3-0.5 mL of sample was loaded onto the center of the pre-cooled lower plate. After adjusting the gap, any remaining sample was scraped off. Dry nitrogen gas was circulated throughout the test to prevent condensation. The temperature was lowered to the target temperature points (-20℃, -40℃, -60℃, -80℃, -100℃) at a rate of 10℃ / min. After the temperature stabilized at each point, the temperature was measured over 1-100 seconds. -1 A steady-state scan was performed within the shear rate range, and the viscosity value was recorded after the torque stabilized.

[0097] Performance 4: Conductivity

[0098] The ionic conductivity of the solution was measured using variable-temperature broadband dielectric spectroscopy.

[0099] An impedance analyzer equipped with a liquid nitrogen cooling system and a parallel plate sealed liquid sample cell (electrodes are made of stainless steel or gold-plated, and the electrode spacing is fixed by insulating gaskets) is used.

[0100] During testing, the sample is injected into the sample cell using a microsyringe, sealed, and installed in a fixture. Dry nitrogen gas is then introduced to prevent condensation.

[0101] The temperature program was set to decrease from room temperature to a series of target temperatures (20℃, 0℃, -20℃, -40℃, -60℃, -80℃, -100℃) at a rate of 5℃ / min, with each temperature point held for 5 minutes. Subsequently, a frequency scan was performed at each isothermal point, ranging from 10^7 Hz to 10^-1 Hz, and the DC conductivity of the solution was extracted by analyzing complex impedance spectroscopy.

[0102] Further comparison can be made using the accompanying diagrams in the instruction manual:

[0103] Figure 1 Differential scanning calorimetry characterization of the anti-crystallization light molecule solution in Example 1 at high water content.

[0104] from Figure 1 As can be seen, the anti-crystallization light molecule solution in Example 1 did not exhibit phase transition behaviors such as crystallization or melting at water contents of 50 mol%, 63 mol%, and 65 mol%, respectively, at low temperatures of -127.30℃, -129.92℃, and -130.47℃. This indicates that our anti-crystallization light molecule solution remains liquid over an ultra-wide temperature range.

[0105] Figure 2 Differential scanning calorimetry characterization of the anti-crystallization light molecule solution in Example 1 at high water content.

[0106] from Figure 2It can be seen that the anti-crystallization light molecule solution of Example 1 undergoes crystallization and melting phase transition in the range of water content as high as 82 mol% to 98 mol%; and as the water content increases, the crystallization temperature gradually increases, and the melting temperature gradually increases.

[0107] Figure 3 Differential scanning calorimetry characterization of the deep eutectic solution of Comparative Example 1 at different molar ratios.

[0108] from Figure 3 It can be seen that the deep eutectic solution of Comparative Example 1 of the present invention exhibits crystallization and melting phenomena at low temperatures; as the molar ratio of EG increases, the crystallization and melting temperatures decrease, and the supercooling performance gradually increases.

[0109] Figure 4 The image shows the temperature-dependent in-situ infrared spectrum of the anti-crystallization light molecule solution in Example 1.

[0110] from Figure 4 As can be seen, in Example 1, water, being the lightest molecular liquid, was precisely diluted, weakening the hydrogen bond network of Comparative Example 1 and providing a controllable perturbation of the interaction strength, with a redshift of the OH bending mode, i.e., from 1410 cm⁻¹. -1 up to 1408 cm -1 The redshift, and the CO stretching from 1044.4 cm -1 Up to 1089.2cm -1 Blue shift.

[0111] Figure 5 The viscosity-temperature dependence curve of the anti-crystallization light molecule solution in Example 1 is shown.

[0112] from Figure 5 It can be seen that in Comparative Example 1, the viscosity suddenly increases as the temperature decreases to around -80°C, indicating that a crystallization phase transition occurred in Comparative Example 1 at this temperature. In contrast to Comparative Example 1, the viscosity in Example 1 decreases steadily as the temperature decreases, indicating that no crystallization phase transition occurred.

[0113] Figure 6 This is a temperature-varying broadband dielectric diagram and structural relaxation characterization diagram of the anti-crystallization light molecule solution in Example 1. Figure 7 The temperature-varying broadband dielectric diagram and conductivity relaxation characterization of the anti-crystallization light molecule solution in Example 1 are presented.

[0114] from Figure 6 The structural relaxation time of Example 1 at different temperatures (0℃, -20℃, -40℃, -60℃, -80℃, -100℃, -120℃, -140℃) can be obtained.

[0115] from Figure 7The conductivity relaxation time of Example 1 at different temperatures (0℃, -20℃, -40℃, -60℃, -80℃, -100℃, -120℃, -140℃) can be obtained.

[0116] contrast Figure 6 and Figure 7 The conduction relaxation time is two orders of magnitude smaller than the structural relaxation time, indicating that the system has a Grotthussian proton conduction mechanism, which is driven by nuclear quantum tunneling.

[0117] Figure 8 : This is the temperature-dependent dielectric diagram-conductivity curve of the anti-crystallization light molecule solution in Example 1. Figure 9 : Temperature dependence of proton jumping activation energy in anti-crystallization light molecule solution in Example 1

[0118] from Figure 8 As can be seen from Example 1, as the temperature decreases, the conductivity dynamics exhibit a transition from super-Arrhenius behavior to sub-Arrhenius motion. This sub-Arrhenius motion is closely related to nuclear quantum tunneling.

[0119] from Figure 9 As can be seen, in Example 1, the activation energy of conductivity decreased anomalously in the low temperature range of -120°C to -140°C, which once again confirms the existence of nuclear quantum tunneling in Example 1.

[0120] The present invention has been described above by way of example with reference to the embodiments and accompanying drawings. Obviously, the implementation of the present invention is not limited to the above-described manner. Any improvements made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A method for preparing an anti-crystallization light molecule solution with an ultrawide supercooling window, characterized in that, Includes the following steps: Step 1: Mix low molecular weight polyols and quaternary ammonium salts under heating conditions to synthesize deep eutectic solvent prepolymers; Step 2: Mix the deep eutectic solvent prepolymer synthesized in Step 1 with water to obtain the anti-crystallization light molecule solution with an ultrawide supercooling window.

2. The method for preparing an anti-crystallization light molecule solution with an ultrawide supercooling window according to claim 1, characterized in that: In step 1, the molar ratio of low molecular weight polyol to quaternary ammonium salt is 7-10:1; the heating conditions are a reaction temperature of 40-80℃, a reaction time of 1-3 hours, and the reaction is carried out under magnetic stirring in an inert gas environment.

3. The method for preparing the anti-crystallization light molecule solution with an ultrawide supercooling window according to claim 1, characterized in that: In step 2, the deep eutectic solvent prepolymer synthesized in step 1 is cooled to room temperature, and water is slowly added in proportion while continuously stirring; the water content is 0.1-0.9 of the total molar amount of the anti-crystallization light molecule solution with an ultra-wide supercooling window.

4. The method for preparing an anti-crystallization light molecule solution with an ultrawide supercooling window according to claim 1, characterized in that: The low molecular weight polyol mentioned in step 1 is a polyol with 2 to 6 carbon atoms.

5. The method for preparing an anti-crystallization light molecule solution with an ultrawide supercooling window according to claim 4, characterized in that: The low molecular weight polyol is one of ethylene glycol, 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, glycerol (glycerol), 1,2,4-butanetriol, 1,2,6-hexanetriol, 1,2,3-propanetriol, pentaerythritol, diethylene glycol, triethylene glycol, methyl propylene glycol (2-methyl-1,3-propanediol), or ethyl ethylene glycol (2-ethyl-1,3-propanediol).

6. The method for preparing an anti-crystallization light molecule solution with an ultrawide supercooling window according to claim 1, characterized in that: The quaternary ammonium salt component mentioned in step 1 has the general formula R. 1 R 2 R 3 R 4 N + X - , Among them, R 1 R 2 R 3 R 4 It is either hydrogen or C1-C4 alkyl, and not both hydrogen at the same time; X - It can be a halide ion, carboxylate ion, hydrogen sulfate ion, or nitrate ion.

7. The method for preparing an anti-crystallization light molecule solution with an ultrawide supercooling window according to claim 1, characterized in that: The water used in step 2 is deionized water, ultrapure water, or reverse osmosis water.

8. A light molecule solution with an ultrawide supercooling window, characterized in that: It is prepared according to the preparation method described in any one of claims 1-7.

9. The anti-crystallization light molecule solution with an ultrawide supercooling window according to claim 8, characterized in that: Its glass transition temperature is below -130℃, and it remains liquid and does not crystallize below -120℃.

10. The use of the anti-crystallization light molecule solution with an ultrawide supercooling window as described in claim 8 in low-temperature heat transfer media, low-temperature electrolytes, low-temperature sensing media, or low-temperature lubrication and sealing media.

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