Device and method for observing ice crystal structure in situ

Abstract

The invention provides a device and method for in-situ observation of an ice crystal structure, and relates to the technical field of freeze drying, the device comprises an optical microscope, a sample table, a temperature sensor unit, a central control system, a refrigeration cycle unit and a low temperature box, the growth process of solvent ice crystals in the freeze drying process is directly observed through the optical microscope, and the temperature sensor unit is connected with the central control system. The relation between the pre-freezing condition and the solvent ice crystal structure is visually reflected, then the relation between the pre-freezing condition and the material micropore structure is indirectly reflected, and the central control system controls the optical microscope to collect information pictures of the ice crystal structure and records the solvent crystallization process of the polymer solution sample to be observed. Therefore, the experiment efficiency is greatly improved, the workload of the freeze-drying process is optimized, and the problem that the growth process and the growth rule of the ice crystals are not directly shown by evidence in the existing freeze-drying technology is solved.

Description

Technical Field

[0001] The invention relates to the technical field of freeze-drying, and in particular to a device and method for in-situ observation of ice crystal structure. Background Art

[0002] Freeze-drying technology uses low-temperature freezing to separate polymer solutions, hydrogels, etc., thereby forming a polymer-rich phase and a solvent-rich phase, respectively. The solvent is then removed in the form of gas under certain conditions to ultimately obtain a porous material. Freeze-drying technology has the advantages of maintaining the chemical structure of the material unchanged, the volume and shape unchanged, high porosity, and high connectivity between pores, and is considered to be a preferred technology for preparing porous materials.

[0003] In the process of preparing porous materials by freeze-drying technology, many tiny solvent ice crystals are usually formed in the polymer solution during pre-freezing. Ice crystals of different shapes and sizes are formed due to different pre-freezing environments. After vacuum drying, the ice crystals sublimate directly, while the material itself remains in the ice crystal frame during pre-freezing, thus forming porous materials with different pore structures. Therefore, the pore structure and pore size of the material can be adjusted by controlling parameters such as solvent type, solvent content, and pre-freezing temperature during the pre-freezing process. The crystallization process and mechanism of the solvent in the polymer solution are relatively complex, involving crystallography, phase change physics, heat and mass transfer, etc. Although the crystallization process of the solvent in the solution is different under different pre-freezing environments, the formation and growth of solvent ice crystals are essentially common. The crystallization of solvent molecules in the solution can be roughly divided into two stages: first, the nucleation of ice crystals, including three-dimensional or two-dimensional nucleation; then, the growth of ice crystals. During the pre-freezing process of the solution, the main factors affecting the nucleation and growth of ice crystals are supercooling, the number of crystallized particles, etc. These parameters determine the microporous structure of the porous material.

[0004] At present, the common method for regulating the microporous structure of porous materials is to change the pre-freezing conditions during freeze-drying, observe the microporous structure after vacuum drying, and finally correlate and analyze the pre-freezing conditions and microporous structure to summarize and derive the relationship between the two. The existing freeze-drying technology only changes the pre-freezing condition parameters, conducts a large number of experiments at the same time, and finally correlates and analyzes the relationship between the pre-freezing parameters and the microporous structure of the material, thereby preparing the porous material with the desired microporous structure; although the solvent ice crystal structure in the freeze-dried solution directly determines the microporous structure of the material, the existing technology has no direct evidence for the growth process and growth law of ice crystals. At the same time, it is not clear how the pre-freezing conditions specifically affect the solvent crystallization process. Therefore, it is urgent to develop a device and method for in-situ observation of ice crystal structure, which is of great significance for understanding the growth process and mechanism of solvent crystals in the solution. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects in the prior art, thereby providing a device and method for in-situ observation of ice crystal structure.

[0006] A device for in-situ observation of ice crystal structure comprises: a microscopic observation system and a sample stage, wherein the microscopic observation system is an optical microscope, the device also comprises a central control system and a low-temperature circulation system, the low-temperature circulation system comprises a refrigeration circulation unit and a low-temperature box, the refrigeration output end and the recovery circulation end of the refrigeration circulation unit are both connected to the low-temperature box, the sample stage is arranged in the low-temperature box, the optical microscope is arranged on the low-temperature box, the optical microscope corresponds to the position of the sample stage, a temperature sensor unit is also arranged on the low-temperature box, and the central control system is signal-connected with the optical microscope, the refrigeration circulation unit and the temperature sensor unit.

[0007] Furthermore, the low temperature box is provided with a refrigerant inlet and a refrigerant outlet, the refrigerant inlet is connected to the refrigeration output end of the refrigeration cycle unit, and the refrigerant outlet is connected to the recovery cycle end of the refrigeration cycle unit.

[0008] Furthermore, the refrigeration cycle unit includes a refrigerator and a low-temperature circulation pump. The refrigerator is arranged in the low-temperature circulation pump. A refrigerant is stored in the refrigerator. The output end of the refrigerator is connected to the low-temperature circulation pump. The refrigeration output end of the low-temperature circulation pump is connected to the refrigerant inlet. The recovery circulation end of the low-temperature circulation pump is connected to the refrigerant outlet.

[0009] Furthermore, the temperature sensor unit is a thermocouple temperature sensor, which is arranged on the low temperature box and is connected to the central control system signal.

[0010] Furthermore, the device also includes pipelines, and the output end of the refrigerator and the low-temperature circulation pump, the refrigeration output end of the low-temperature circulation pump and the refrigerant inlet, and the recovery circulation end of the low-temperature circulation pump and the refrigerant outlet are connected through different pipelines.

[0011] Furthermore, the central control system is a computer, and the computer is connected to the optical microscope, the low-temperature circulation pump and the thermocouple temperature sensor signal.

[0012] Furthermore, the device also includes an illuminating lamp, which is arranged on the optical microscope.

[0013] Furthermore, the cryogenic box is a sandwich structure, the cryogenic box comprises an inner layer and an outer layer, the sample stage is arranged inside the inner layer, and the cold medium inlet and the cold medium outlet are both opened on the outer layer of the cryogenic box.

[0014] Furthermore, the magnification range of the optical microscope is 0 to 1000 times.

[0015] The present invention also includes a method for in-situ observation of ice crystal structure, which is implemented based on a device for in-situ observation of ice crystal structure as described in any of the above items. The central control system controls the refrigeration cycle speed of the refrigeration cycle unit according to the temperature data provided by the temperature sensor unit, thereby controlling the internal temperature of the low-temperature box to reach the required experimental temperature, pouring the polymer solution sample to be observed into the sample table, and controlling the optical microscope through the central control system to collect ice crystal structure information pictures and record the solvent crystallization process of the polymer solution sample to be observed.

[0016] The technical solution of the present invention has the following advantages:

[0017] In the technical solution provided by the present invention, the growth process of solvent ice crystals during freeze-drying is directly observed through an optical microscope, which intuitively reflects the relationship between the pre-freezing conditions and the solvent ice crystal structure, and then indirectly reflects the relationship between the pre-freezing conditions and the microporous structure of the material. The central control system controls the optical microscope to collect ice crystal structure information images and record the solvent crystallization process of the polymer solution sample to be observed, thereby greatly improving the experimental efficiency and optimizing the workload of the freeze-drying process. By observing the ice crystal growth process in situ, the pre-freezing parameters can be better controlled to prepare porous materials with controllable and adjustable microporous structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0020] Figure 2 This is a picture of ice crystals collected during the crystallization process of the solution in Experimental Example 1 of the present invention;

[0021] Figure 3 This is a picture of ice crystals collected during the crystallization process of the solution in Experimental Example 2 of the present invention;

[0022] Figure 4 This is a picture of ice crystals collected during the crystallization process of the solution in Experimental Example 3 of the present invention;

[0023] Figure 5 This is a picture of ice crystals collected during the crystallization process of the solution in Experimental Example 4 of the present invention.

[0024] Description of reference numerals:

[0025] 1-computer; 2-optical microscope; 3-low temperature circulation pump; 4-low temperature box; 4-1-refrigerant medium inlet; 4-2-refrigerant medium outlet; 4-3-temperature sensor unit; 5-sample stage. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0028] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] like Figure 1The device shown in the figure is a device for in-situ observation of ice crystal structure, comprising: a microscopic observation system and a sample stage 5, wherein the microscopic observation system is an optical microscope 2, the device also comprises a central control system and a low temperature circulation system, the low temperature circulation system comprises a refrigeration circulation unit and a low temperature box 4, the refrigeration output end and the recovery circulation end of the refrigeration circulation unit are both connected to the low temperature box 4, the sample stage 5 is arranged in the low temperature box 4, the optical microscope 2 is arranged on the low temperature box 4, the objective lens of the optical microscope 2 is located in the low temperature box 4, and the position of the objective lens of the optical microscope 2 corresponds to that of the sample stage 5, the low temperature box 4 is also provided with a temperature sensor unit 4-3, the central control system is connected to the optical microscope 2, the refrigeration circulation unit and the temperature sensor unit 4-3, the optical microscope 2 is The maximum magnification range is 0 to 1000 times; the central control system is used to control the microscopic observation system and the low-temperature circulation system, and the central control system can receive, process and output information; the optical microscope 2 collects and records the image information of the polymer solution sample whose crystallization process is to be observed according to the control of the central control system; the refrigeration circulation unit cools the low-temperature box 4 and the solution sample; the sample table 5 is used to hold the polymer solution sample whose crystallization process is to be observed, and the device also includes a container and a cover glass. The container is used to hold the polymer solution sample to be observed, and the cover glass is a highly light-transmittance glass. The cover glass is used to form a flat layer of uniform thickness for the liquid sample to facilitate observation. The temperature sensor unit 4-3 is used to monitor the internal temperature of the low-temperature box 4.

[0031] The above-mentioned device for in-situ observation of ice crystal structure directly observes the growth process of solvent ice crystals during freeze-drying process through optical microscope 2, intuitively reflects the relationship between pre-freezing conditions and solvent ice crystal structure, and then indirectly reflects the relationship between pre-freezing conditions and material microporous structure. The central control system controls the optical microscope 2 to collect ice crystal structure information pictures and record the solvent crystallization process of the polymer solution sample to be observed, thereby greatly improving the experimental efficiency and optimizing the workload of the freeze-drying process. By observing the ice crystal growth process in situ, the pre-freezing parameters can be better controlled to prepare porous materials with controllable and adjustable microporous structure.

[0032] like Figure 1As shown, in this embodiment, a refrigerant inlet 4-1 and a refrigerant outlet 4-2 are provided on the cryogenic box 4, the cryogenic box 4 is a sandwich structure, the cryogenic box 4 includes an inner layer and an outer layer, the sample table 5 is arranged inside the inner layer, and the refrigerant inlet 4-1 and the refrigerant outlet 4-2 are both provided on the outer layer of the cryogenic box 4; the refrigerant inlet 4-1 is connected to the refrigeration output end of the refrigeration cycle unit, and the refrigerant outlet 4-2 is connected to the recovery cycle end of the refrigeration cycle unit; the refrigeration cycle unit includes a refrigerator and a low-temperature circulation pump 3, the refrigerator is arranged in the low-temperature circulation pump 3, a refrigerant is stored in the refrigerator, the output end of the refrigerator is connected to the low-temperature circulation pump 3, the refrigeration output end of the low-temperature circulation pump 3 is connected to the refrigerant inlet 4-1, and the recovery cycle end of the low-temperature circulation pump 3 is connected to the refrigerant outlet 4-2; the device also includes a pipeline, between the output end of the refrigerator and the low-temperature circulation pump 3, between the refrigeration output end of the low-temperature circulation pump 3 and the refrigerant inlet 4-1, and between the recovery cycle end of the low-temperature circulation pump 3 and the refrigerant outlet 4-2. The refrigerator cools the refrigerant, and transports the refrigerated refrigerant to the low-temperature circulation pump 3 through the output end and pipeline of the refrigerator. The low-temperature circulation pump 3 transports the refrigerated refrigerant to the sandwich structure of the low-temperature box 4 through the refrigeration output end, pipeline and refrigerant inlet 4-1, and at the same time recycles the refrigerant to the low-temperature circulation pump 3 through the refrigerant outlet 4-2, pipeline and recovery circulation end. In this way, the refrigerant circulates in the sandwich structure of the low-temperature box 4 to reduce the internal temperature of the low-temperature box 4, and the refrigerant in the sandwich structure continuously provides refrigeration to the low-temperature box 4; the design of the sandwich structure can effectively isolate the conduction of external heat, reduce heat exchange, thereby maintaining the low temperature environment of the inner layer, and improving the insulation efficiency. At the same time, if the refrigerant is directly transported to the inner layer of the low-temperature box 4, it will affect the experimental environment and make the experiment unable to be carried out. Therefore, the low-temperature box 4 is designed as a double-layer sandwich structure; the refrigeration temperature of the refrigerator is room temperature to minus 196°C, and the cooling rate is 0 to 10°C / min, which meets the experimental requirements.

[0033] like Figure 1 As shown, in this embodiment, the temperature sensor unit 4-3 is a thermocouple temperature sensor, which is arranged on the low temperature box 4 and is connected to the central control system signal; the temperature sensor unit 4-3 can also be a thermistor temperature sensor or an optical fiber temperature sensor. Thermocouple temperature sensors, thermistor temperature sensors and optical fiber temperature sensors can measure temperature more accurately, provide accurate data support for the central control system and thus ensure the progress of the experiment.

[0034] like Figure 1As shown, in this embodiment, the central control system is a computer 1, and the computer 1 is connected to the optical microscope 2, the low-temperature circulation pump 3 and the thermocouple temperature sensor signal. When the temperature sensor unit 4-3 is a thermistor temperature sensor or an optical fiber temperature sensor, the thermistor temperature sensor or the optical fiber temperature sensor is correspondingly connected to the computer 1 signal. The computer 1 controls the operation of the optical microscope 2, the low-temperature circulation pump 3, the thermocouple temperature sensor, the thermistor temperature sensor and the optical fiber temperature sensor, and is the central control system of the entire device.

[0035] like Figure 1 As shown, in this embodiment, the device also includes an illumination lamp, which is arranged on the optical microscope 2; the illumination lamp light source modes include central illumination, oblique illumination, bright field illumination, dark field illumination, coaxial illumination, scattered illumination, polarized illumination, and fluorescent illumination. The various illumination modes meet the illumination requirements for recording the solvent crystallization process of the solution sample during the experiment.

[0036] like Figure 1 to Figure 4 As shown, the present invention also includes a method for in-situ observation of ice crystal structure, which is implemented based on a device for in-situ observation of ice crystal structure described in any one of the above items, wherein the central control system controls the refrigeration cycle speed of the refrigeration cycle unit according to the temperature data provided by the temperature sensor unit 4-3, thereby controlling the internal temperature of the low-temperature box 4 to reach the required temperature of the experiment, pouring the polymer solution sample to be observed into the sample stage 5, and controlling the optical microscope 2 through the central control system to collect ice crystal structure information pictures and record the solvent crystallization process of the polymer solution sample to be observed;

[0037] Specifically, the computer 1 controls the refrigeration cycle speed of the low-temperature circulation pump 3 according to the temperature data provided by the thermocouple temperature sensor, the thermal resistance temperature sensor or the optical fiber temperature sensor, thereby controlling the internal temperature of the low-temperature box 4 to reach the required temperature of the experiment, pouring the polymer solution sample to be observed into the sample stage 5, covering it with a cover glass, and controlling the optical microscope 2 through the microscope control software in the computer 1 to collect ice crystal structure information pictures and record the solvent crystallization process of the polymer solution sample to be observed;

[0038] The following experimental examples were conducted based on the above-mentioned method for in-situ observation of ice crystal structure:

[0039] Experimental Example 1: Computer 1 adjusts the refrigeration temperature of the low-temperature circulation pump 3 to 0°C. Computer 1 controls the refrigeration cycle speed of the low-temperature circulation pump 3 according to the temperature data provided by the thermocouple temperature sensor, the thermal resistor temperature sensor or the optical fiber temperature sensor, until the internal temperature of the low-temperature box 4 feedback from the thermocouple temperature sensor, the thermal resistor temperature sensor or the optical fiber temperature sensor reaches 0°C. A 5% concentration of polyurethane dioxane solution is poured into the sample stage 5 in the low-temperature box 4, covered with a cover glass, and the microscope control software in the computer 1 is opened. The magnification of the optical microscope 2 is adjusted to 100 times, and the sample is collected. Figure 2 Picture of ice crystals during crystallization of solution shown;

[0040] Experimental Example 2: Computer 1 adjusts the refrigeration temperature of the low-temperature circulation pump 3 to minus 80°C. Computer 1 controls the refrigeration cycle speed of the low-temperature circulation pump 3 according to the temperature data provided by the thermocouple temperature sensor, the thermal resistor temperature sensor or the optical fiber temperature sensor, until the internal temperature of the low-temperature box 4 feedback from the thermocouple temperature sensor, the thermal resistor temperature sensor or the optical fiber temperature sensor reaches 0°C. A 5% concentration of polyurethane dioxane solution is poured into the sample stage 5 in the low-temperature box 4, covered with a cover glass, and the microscope control software in the computer 1 is opened. The magnification of the optical microscope 2 is adjusted to 200 times, and the sample is collected. Figure 3 Picture of ice crystals during crystallization of solution shown;

[0041] Experimental Example 3: Computer 1 adjusts the refrigeration temperature of the low-temperature circulation pump 3 to minus 40°C. Computer 1 controls the refrigeration cycle speed of the low-temperature circulation pump 3 according to the temperature data provided by the thermocouple temperature sensor, the thermal resistor temperature sensor or the optical fiber temperature sensor, until the internal temperature of the low-temperature box 4 feedback from the thermocouple temperature sensor, the thermal resistor temperature sensor or the optical fiber temperature sensor reaches 0°C. A 5% concentration of a mixed solution of polyurethane dioxane and dimethyl sulfoxide (the volume ratio of dioxane to dimethyl sulfoxide is 96:4) is poured into the sample stage 5 in the low-temperature box 4, covered with a cover glass, and the microscope control software in the computer 1 is opened. The magnification of the optical microscope 2 is adjusted to 200 times, and the sample is collected. Figure 4 Picture of ice crystals during crystallization of solution shown;

[0042] Experimental Example 4: Computer 1 adjusts the refrigeration temperature of the low-temperature circulation pump 3 to 0°C. Computer 1 controls the refrigeration cycle speed of the low-temperature circulation pump 3 according to the temperature data provided by the thermocouple temperature sensor, the thermal resistor temperature sensor or the optical fiber temperature sensor, until the internal temperature of the low-temperature box 4 feedback from the thermocouple temperature sensor, the thermal resistor temperature sensor or the optical fiber temperature sensor reaches 0°C. A 7% concentration of polyurethane dioxane solution is poured into the sample stage 5 in the low-temperature box 4, covered with a cover glass, and the microscope control software in the computer 1 is opened. The magnification of the optical microscope 2 is adjusted to 200 times, and the sample is collected. Figure 5 Picture of ice crystals during crystallization of a solution shown.

[0043] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A device for in-situ observation of ice crystal structure, comprising: A microscopic observation system and a sample stage (5), characterized in that the microscopic observation system is an optical microscope (2), the device also includes a central control system and a low-temperature circulation system, the low-temperature circulation system includes a refrigeration circulation unit and a low-temperature box (4), the refrigeration output end and the recovery circulation end of the refrigeration circulation unit are both connected to the low-temperature box (4), the sample stage (5) is arranged in the low-temperature box (4), the optical microscope (2) is arranged on the low-temperature box (4), the optical microscope (2) and the sample stage (5) are located correspondingly, the low-temperature box (4) is also provided with a temperature sensor unit (4-3), and the central control system is signal-connected to the optical microscope (2), the refrigeration circulation unit and the temperature sensor unit (4-3).

2. The device for in-situ observation of ice crystal structure according to claim 1, characterized in that: The low temperature box (4) is provided with a cold medium inlet (4-1) and a cold medium outlet (4-2); the cold medium inlet (4-1) is connected to the refrigeration output end of the refrigeration cycle unit, and the cold medium outlet (4-2) is connected to the recovery cycle end of the refrigeration cycle unit.

3. The device for in-situ observation of ice crystal structure according to claim 2, characterized in that: The refrigeration cycle unit comprises a refrigerator and a low-temperature circulation pump (3), the refrigerator is arranged in the low-temperature circulation pump (3), a refrigerant is stored in the refrigerator, an output end of the refrigerator is connected to the low-temperature circulation pump (3), a refrigeration output end of the low-temperature circulation pump (3) is connected to a refrigerant inlet (4-1), and a recovery circulation end of the low-temperature circulation pump (3) is connected to a refrigerant outlet (4-2).

4. The device for in-situ observation of ice crystal structure according to claim 3, characterized in that: The temperature sensor unit (4-3) is a thermocouple temperature sensor, which is arranged on the low temperature box (4) and is connected to the central control system signal.

5. The device for in-situ observation of ice crystal structure according to claim 3, characterized in that: The device also includes pipelines, and the output end of the refrigerator and the low-temperature circulation pump (3), the refrigeration output end of the low-temperature circulation pump (3) and the cold medium inlet (4-1), and the recovery circulation end of the low-temperature circulation pump (3) and the cold medium outlet (4-2) are connected through different pipelines.

6. The device for in-situ observation of ice crystal structure according to claim 4, characterized in that: The central control system is a computer (1), and the computer (1) is connected to the optical microscope (2), the low-temperature circulation pump (3) and the thermocouple temperature sensor signal.

7. The device for in-situ observation of ice crystal structure according to claim 1, characterized in that: The device also includes an illuminating lamp, which is arranged on the optical microscope (2).

8. The device for in-situ observation of ice crystal structure according to claim 2, characterized in that: The cryogenic box (4) is a sandwich structure, comprising an inner layer and an outer layer, the sample stage (5) is arranged inside the inner layer, and the cold medium inlet (4-1) and the cold medium outlet (4-2) are both opened on the outer layer of the cryogenic box (4).

9. The device for in-situ observation of ice crystal structure according to claim 1, characterized in that: The magnification range of the optical microscope (2) is 0 to 1000 times.

10. A method for in-situ observation of ice crystal structure, the method is implemented based on the device for in-situ observation of ice crystal structure according to any one of claims 1 to 9, characterized in that: The central control system controls the refrigeration cycle speed of the refrigeration cycle unit according to the temperature data provided by the temperature sensor unit (4-3), thereby controlling the internal temperature of the low-temperature box (4) to reach the experimental required temperature, pouring the polymer solution sample to be observed into the sample table (5), and controlling the optical microscope (2) through the central control system to collect ice crystal structure information images and record the solvent crystallization process of the polymer solution sample to be observed.

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