Rheological-birefringence-small angle light scattering combined in-situ testing device and method

Abstract

The invention discloses a rheology-birefringence-small-angle light scattering combined in-situ testing device and method, relates to the technical field of high polymer material performance testing, and solves the problem that an existing Rheo-SALS device cannot synchronously measure macro-scale stress-strain response, mesoscale sample structure information, micro-scale birefringence signals, large-scale sample structure information and large-scale sample structure information in situ. And the energy loss of a traditional straight light path is large. According to the device, inclined light / straight light dual light paths are designed, the straight light path adopts a reflecting prism to guide laser to vertically enter a sample, and a CMOS camera is matched to collect a scattering image, so that the light energy utilization rate is remarkably improved; the oblique light path is arranged along 45 degrees, and the birefringence is measured by combining a chopper and a photoelectric detector. The radial distances of the detection samples are the same by adjusting the positions of the light spots of the two light paths, and the flow field gradient difference is eliminated. According to the invention, in-situ synchronous measurement of multi-layer structure information is realized, and the structure-function relationship between high-molecular stress response and structural evolution is accurately revealed.

Description

Technical Field

[0001] This invention relates to the field of polymer material performance testing technology, specifically to an in-situ testing device and method combining rheology, birefringence, and small-angle light scattering. Background Technology

[0002] In practical applications, most polymer systems are not monolithic systems, but rather blends of multiple polymers or complexes of polymers and fillers. For multiphase, multicomponent polymer systems, it is difficult to obtain microscopic dynamic information of multiple components simultaneously at the molecular level using a single characterization method.

[0003] Classical polymer rheometers study the mechanical properties of composite polymer materials by measuring macroscopic stress-strain responses and combining them with polymer dynamics theory. However, rheological techniques cannot directly obtain information on molecular conformational dynamics, making it difficult to clarify the structure-property relationship between the multi-level structure of polymers and macroscopic mechanical properties. The combined rheology and optics technique can overcome the limitation of traditional rheometers, which can only measure stress-strain responses, and helps to elucidate this relationship. The "rheology-birefringence" combined technique based on the stress optical rule can simultaneously measure stress and birefringence. By leveraging the different weights of chain segment orientation in stress and birefringence signals, it can achieve component analysis of corresponding forces. Combined with small-angle light scattering (SALS) technology, the research scale can be extended from the chain segment scale to the mesoscopic scale, thereby analyzing the contribution of mesoscopic structures such as interfaces to corresponding forces. The development of these combined techniques helps guide the molecular design and optimization of processing conditions for specific stress-responsive polymer systems.

[0004] In existing technologies, Jörg Läuger's team disclosed "Rheo Small Angle Light Scattering (Rheo-SALS) and Rheo-Microscopy as tools for investigations of structure-property relations in complex fluids," such as... Figure 1 and Figure 2 As shown, the rheology-small-angle light scattering (Rheo-SALS) device has been developed and commercialized by Anton Paar in Austria. While the Rheo-SALS device can simultaneously test rheological properties and small-angle light scattering, the small-angle light scattering test scattering vector range is (0.3 μm). -1 ≤ q ≤ 2.0 μm -1 However, it cannot achieve simultaneous in-situ measurement of macroscopic-scale stress-strain response, mesoscopic-scale sample structural information, and microscopic-scale birefringence signals. Summary of the Invention

[0005] This invention solves the technical problem that the Rheo-SALS device cannot achieve synchronous in-situ measurement of macroscopic-scale stress-strain response, mesoscopic-scale sample structural information, and microscopic-scale birefringence signal.

[0006] The rheology-birefringence-small-angle light scattering combined in-situ testing device of the present invention includes a straight optical path consisting of a first laser emitter, a first polarizer, a reflecting prism, a polymer sample, a first analyzer and a CMOS camera placed in sequence. It also includes a slanted optical path consisting of a second laser emitter, a second polarizer, a chopper, a polymer sample, a quarter-wave plate, a second analyzer, and a photodetector, which are placed sequentially at a 45° angle along the horizontal plane. Commercial rheometers apply shear flow fields to polymer samples.

[0007] The in-situ testing method combining rheology, birefringence, and small-angle light scattering described in this invention is based on the aforementioned in-situ testing device combining rheology, birefringence, and small-angle light scattering, and specifically comprises: The lasers emitted from the straight and oblique optical paths pass through the polymer sample simultaneously, and the commercial rheometer applies a shear flow field to the polymer sample.

[0008] Furthermore, in one embodiment of the present invention, the laser emitted from the oblique optical path passes through the polymer sample, specifically as follows: The second laser emitter emits laser light at a 45° angle to the horizontal plane. The laser light is converted into linearly polarized light by the second polarizer. After the linearly polarized light is modulated by a rotating chopper, it passes through a polymer sample under deformation conditions between optical glass plates.

[0009] Furthermore, in one embodiment of the present invention, after the polymer sample passes through the optical glass plate under deformation conditions, it passes through a quarter-wave plate and a second polarizer in sequence before entering a photodetector for photoelectric signal detection.

[0010] Furthermore, in one embodiment of the present invention, the laser emitted from the direct optical path passes through the polymer sample, specifically as follows: The first laser emitter emits laser light, which is converted into linearly polarized light by the first polarizer. After being reflected by a reflecting prism, the linearly polarized light passes through a polymer sample under deformation conditions between optical glass plates.

[0011] Furthermore, in one embodiment of the present invention, after the polymer sample is subjected to deformation conditions between optical glass plates, it passes through a first analyzer and enters a CMOS camera for signal acquisition.

[0012] This invention solves the technical problem that the Rheo-SALS device cannot achieve simultaneous in-situ measurement of macroscopic-scale stress-strain response, mesoscopic-scale sample structural information, and microscopic-scale birefringence signals. Specific beneficial effects include: 1. This invention proposes a combined in-situ testing method using rheology-birefringence-small-angle light scattering (SALS). Based on the combined rheology-birefringence technique, the simultaneous use of SALS allows for the detection of mesoscopic condensed-state structural information closely related to mechanical response. This enables simultaneous, in-situ testing of macroscopic mechanical properties and mesoscopic / molecular-scale structural information in multiphase, multi-component systems. The resulting combined rheology-birefringence-small-angle light scattering in-situ testing device can simultaneously reveal the relationship between polymer stress response and the evolution of anisotropic chain structures and mesoscopic structures, providing an effective technical solution for clarifying the structure-property relationship between multi-level structures and mechanical properties. 2. This invention proposes an in-situ testing method combining rheology, birefringence, and small-angle light scattering. It integrates a small-angle light scattering test module and a birefringence test module on a commercial rheometer (Anton Paar MCR702 rheometer) to achieve simultaneous in-situ measurement of rheological properties of polymer materials, small-angle light scattering test, and birefringence test. Attached Figure Description

[0013] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a drawing of the Rheo-SALS device described in the background art; Figure 2 This is a diagram of the Rheo-SALS device described in the background section; Figure 3 3. (a) is a diagram of the in-situ testing device for rheology-birefringence-small-angle light scattering combined as described in Embodiment 1. 3. (b) is a physical diagram of the in-situ testing device for rheology-birefringence-small-angle light scattering combined as described in the background art. Figure 4 This is a diagram of the in-situ testing device for rheology-small-angle light scattering combined as described in Embodiment 1; Figure 5 These are transmission electron microscope (TEM) images of the hydrophilic spherical SiO2 aqueous dispersion system described in Embodiment 2; Figure 6 This is the blank background image without added SiO2 as described in Embodiment 2, wherein the scattering image size integration direction is indicated by the white straight line; Figure 7 The following are sample scattering diagrams under different shear rates as described in Embodiment 2. 7.(a) Shear rate: 0 s -1 7.(b) Shear rate: 5 s-1 7.(c) Shear rate: 10 s -1 7.(d) Shear rate: 20 s -1 ; Figure 8 (a) is a 1D scattering curve of the SiO2 water dispersion system under different shear rate conditions as described in Embodiment 2. The dashed line is the scattering characteristic peak. (b) is a shear viscosity curve of the SiO2 water dispersion system under different shear rate conditions. Detailed Implementation

[0014] Various embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. The embodiments described with reference to the drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0015] Implementation Method 1: This implementation method aims to solve the technical problem that the Rheo-SALS device cannot achieve synchronous in-situ measurement of macroscopic-scale stress-strain response, mesoscopic-scale sample structural information, and microscopic-scale birefringence signals.

[0016] To address the aforementioned technical problems, this embodiment, during the development of the "Rheology-Birefringence Combined In-situ Testing Device and Method Based on Chopper Rotation Frequency Signal" disclosed in Chinese Patent 202511847689.6, discovered that this testing device has the characteristic of in-situ synchronous measurement of macroscopic stress response and microscopic birefringence signal of polymer system, and is suitable for the oblique light path described in this embodiment, thus solving the technical problems to be addressed in this embodiment. Therefore, this embodiment improves upon this testing device by adapting it to a straight light path that can cooperate with the oblique light path.

[0017] Regarding the straight optical path, Chinese patent CN112748042A discloses "An optical microrheology device and method for characterizing the viscoelasticity of soft matter". It uses a laser 1 as a light source, and the emitted coherent light passes through a polarizer 2 and a beam splitter 3, and is then focused into the sample cell 5 by a focusing lens 4. This optical path achieves the purpose of a straight optical path. Therefore, this embodiment combines it with the aforementioned oblique optical path to solve the technical problem to be addressed. However, in actual operation, the straight optical path suffers from severe light energy loss when the coherent light enters the beam splitter (with a 50:50 split, the light energy utilization rate is only 25%) due to the presence of a beam splitter. This results in low light energy utilization and poor high-frequency response. When combined with the aforementioned oblique optical path, it produces poor quality sample scattering images under high shear rate conditions, making quantitative analysis impossible. Therefore, it cannot solve the technical problem to be addressed in this embodiment.

[0018] To address the aforementioned technical problems, this embodiment further improves the direct optical path by introducing a reflecting prism, which typically has an energy transmission efficiency greater than 98%, thus resolving the aforementioned technical issues. It is important to emphasize that the improved direct and oblique optical paths require adjustment of their spot positions to ensure simultaneous measurement of sample information at the same radial distance from the fixture center. This eliminates differences in the flow field gradient, forming a combined rheological-birefringence-small-angle light scattering in-situ testing device. This device effectively reveals the relationship between polymer stress response and the evolution of anisotropic chain structure and mesoscopic structure, providing a powerful technical solution for clarifying the structure-property relationship between multi-level structures and mechanical properties. Specifically, this combined rheological-birefringence-small-angle light scattering in-situ testing device is as follows: like Figure 3 As shown, a dual-optical-path "oblique / straight" system was designed. Utilizing components such as a laser emitter, polarizer, chopper, analyzer, CMOS camera, and photodetector, an in-situ testing device combining rheology, birefringence, and small-angle light scattering was constructed based on the commercially available MCR702 (Anton Paar) rheometer. This combined macroscopic mechanical behavior from rheological testing, mesoscopic condensed-state structural information from small-angle light scattering detection, and stress-optical response resolved from dynamic birefringence to elucidate the structure-property relationship between multi-level structures and mechanical properties in polymer samples.

[0019] For the oblique light path, the second laser emitter emits laser light at a 45° angle to the horizontal plane. The laser light is converted into linearly polarized light by the second polarizer. After the linearly polarized light is modulated by the rotating chopper, it passes through the polymer sample under deformation conditions between the optical glass plates, and then passes through the quarter wave plate and the second analyzer in sequence before entering the photodetector for photoelectric signal detection.

[0020] For a straight optical path, the first laser emitter emits laser light, which is converted into linearly polarized light by the first polarizer. After the linearly polarized light is reflected by the reflecting prism, it passes through the polymer sample under deformation conditions between the optical glass plates, then through the first analyzer, and finally enters the CMOS camera for signal acquisition.

[0021] Commercial rheometers apply shear flow fields to polymer samples.

[0022] Among them, such as Figure 4 As shown, the laser beam enters the sample through a polarizer and a reflecting prism, forming an angle with the sample surface. A straight light path is formed, scattering occurs, the light passes through the analyzer, enters the CMOS camera, and forms a scattered image on the photosensitive element. The distance from the sample to the photosensitive element is... The size of the scattering image is: (1) in, It is the size of the pixel (3.2μm / pixel). and This refers to the pixel location. The scattering angle is: (2) The scattering vector is then defined as: (3) in, It is the laser wavelength. The intensity of the scattered light at the corresponding pixel in the scattering image. It can be parsed and drawn by a Python image recognition script. The relationship curves were used as a basis to analyze the mesoscale structural information of polymer samples under the shear flow field applied by the Anton Paar MCR702 rheometer.

[0023] Based on the simultaneous in-situ testing of rheological properties and small-angle light scattering, a birefringence testing module can be further integrated to achieve simultaneous in-situ testing of rheological properties, small-angle light scattering, and birefringence of polymer materials.

[0024] It should be noted that the improved straight and oblique optical paths need to work together. The lasers emitted by the straight and oblique optical paths must pass through polymer samples with the same radial distance to simultaneously reveal the relationship between polymer stress response and the evolution of anisotropic chain structure and mesoscopic structure. This provides an effective technical solution for clarifying the structure-property relationship between multi-level structures and mechanical properties. If the lasers emitted by the straight and oblique optical paths cannot pass through polymer samples with the same radial distance simultaneously, the optical signal (birefringence / scattering) and the rheological signal (stress / strain) will lose their strict correspondence. This will prevent the accurate revelation of the true structural evolution mechanism under specific stress responses, and will also fail to solve the technical problem that this embodiment aims to address.

[0025] Implementation Method Two: To better illustrate the technical effects of Implementation Method One, this implementation method will be described in detail: The test was conducted using a commercially available hydrophilic spherical SiO2 aqueous dispersion system. The size distribution ranged from 0.2 to 5.0 μm, with a medium particle size of: Transmission electron microscopy (TEM) images of the samples are as follows: Figure 5 As shown. The mass concentration of the test sample is: .

[0026] The CMOS camera sensor has a resolution of 4096*3072 pixels. The blank background image without the sample is shown below. Figure 6 As shown, no scattering occurs. The scattering image size integration direction is as follows: Figure 6 As shown by the white straight line.

[0027] Scattering images of SiO2 aqueous dispersion system under different shear rates are shown below. Figure 7 As shown, the shear rate is 0 s. -1 When the shear rate increases, scattering occurs. As the shear rate gradually increases, the scattering phenomenon gradually intensifies, and the image brightness increases significantly.

[0028] The 1D scattering curve calculated by formula (1-3) is as follows: Figure 8 As shown in Figure a, the dashed line represents the scattering characteristic peak, and its corresponding spatiotemporal size is the average spacing between SiO2 aggregates. d It can be calculated using formula (4). Figure 8 Curve b shows the shear viscosity curves of the SiO2 aqueous dispersion system under different shear rate conditions.

[0029] (4) The mesoscopic scale information of the SiO2 aqueous dispersion system can be calculated using the following formula: (5) (6) (7) (8) in, The vector position corresponding to the scattering characteristic peak. Medium particle size, This refers to the volume fraction of SiO2. This refers to the mass concentration of SiO2. This represents the volume occupied by SiO2 in the dispersed system. This is the theoretical value of the average spacing between SiO2 aggregates.

[0030] Calculated The self-designed in-situ rheology-small-angle light scattering combined testing device demonstrates that the small-angle light scattering testing module operates normally, and the scattering vector measurement range is (0.1μm). -1 ≤ q ≤4.0μm -1 It is larger than the testing range of commercial Rheo-SALS (0.3μm). -1 ≤ q ≤2.0μm -1 The test results of this device are consistent with the theoretical calculation results of the SiO2 water dispersion system.

[0031] The above describes the in-situ testing device and method combining rheology, birefringence, and small-angle light scattering proposed in this invention. This document provides a detailed description and uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A rheological-birefringence-small-angle light scattering combined in-situ testing device, characterized in that, The device includes a straight optical path consisting of a first laser emitter, a first polarizer, a reflecting prism, a polymer sample, a first analyzer, and a CMOS camera placed in sequence. It also includes a slanted optical path consisting of a second laser emitter, a second polarizer, a chopper, a polymer sample, a quarter-wave plate, a second analyzer, and a photodetector, which are placed sequentially at a 45° angle along the horizontal plane. Commercial rheometers apply shear flow fields to polymer samples.

2. A combined in-situ testing method for rheology-birefringence-small-angle light scattering, wherein the testing method is based on the combined in-situ testing device for rheology-birefringence-small-angle light scattering as described in claim 1, characterized in that... Specifically: The lasers emitted from the straight and oblique optical paths pass through the polymer sample simultaneously, and the commercial rheometer applies a shear flow field to the polymer sample.

3. The in-situ testing method combining rheology, birefringence, and small-angle light scattering according to claim 2, characterized in that, The laser emitted from the oblique optical path passes through the polymer sample, specifically as follows: The second laser emitter emits laser light at a 45° angle to the horizontal plane. The laser light is converted into linearly polarized light by the second polarizer. After the linearly polarized light is modulated by a rotating chopper, it passes through a polymer sample under deformation conditions between optical glass plates.

4. The in-situ testing method combining rheology, birefringence, and small-angle light scattering according to claim 3, characterized in that, After passing through the optical glass plates under deformation conditions, the polymer sample then passes through a quarter-wave plate and a second analyzer before entering a photodetector for photoelectric signal detection.

5. The in-situ testing method combining rheology, birefringence, and small-angle light scattering according to claim 2, characterized in that, The laser emitted from the direct optical path passes through the polymer sample, specifically as follows: The first laser emitter emits laser light, which is converted into linearly polarized light by the first polarizer. After being reflected by a reflecting prism, the linearly polarized light passes through a polymer sample under deformation conditions between optical glass plates.

6. The in-situ testing method combining rheology, birefringence, and small-angle light scattering according to claim 5, characterized in that, After passing through the optical glass plates under deformation conditions, the polymer sample then passes through the first analyzer and enters the CMOS camera for signal acquisition.

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