A flexible material deformation-induced droplet bridging test device

Abstract

This invention provides a testing device for deformation-induced droplet bridging in flexible materials. The device includes: a base support mechanism; a sample fixing mechanism mounted on the base support mechanism; a deformation loading mechanism mounted on the base support mechanism and connected to the sample fixing mechanism; a droplet array generation mechanism positioned above the sample fixing mechanism; an image acquisition mechanism mounted on the base support mechanism; and a data processing mechanism electrically connected to both the image acquisition mechanism and the deformation loading mechanism. This invention integrates deformation loading, droplet array generation, image acquisition, and data processing into a single unit, simultaneously obtaining the deformation parameters, droplet array changes, and droplet bridging states of the flexible material under test within the same testing sequence. This effectively solves the problem in existing technologies where it is difficult to conduct in-situ observation and evaluation of multi-droplet bridging behavior under deformation conditions.

Description

Technical Field

[0001] This invention relates to the field of functional material wetting performance testing technology, and more specifically, to a flexible material deformation-induced droplet bridging testing device. Background Technology

[0002] Superhydrophobic materials typically refer to materials with a high contact angle and a low roll-off angle to water. Their surfaces allow water droplets to exist in an approximately spherical shape and roll off or detach under relatively small external forces. Due to their excellent water repellency, self-cleaning, anti-condensation, anti-fouling, and anti-icing potential, these materials have attracted widespread attention in fields such as electrical insulation protection, anti-flashover, outdoor equipment surface protection, flexible waterproof materials, and porous functional materials. Compared to traditional rigid coating materials, flexible superhydrophobic bulk materials usually have a certain thickness, elastic deformation capacity, and internal porous structure. Under compression, tension, bending, or cyclic loading, their surface morphology, pore spacing, local roughness structure, and droplet contact state may all change. Therefore, the water repellency of flexible superhydrophobic bulk materials depends not only on the contact angle and roll-off angle under static conditions but also on their ability to maintain droplet dispersion under deformation conditions.

[0003] Current methods for testing the wetting properties of superhydrophobic materials primarily employ static contact angle testing, roll-off angle testing, droplet observation, or single-droplet impact testing. While these methods can evaluate the spreading, adhesion, and rolling behavior of individual droplets on the material surface, they are mostly conducted in a static state where the material has not undergone significant deformation, and the test objects are typically single droplets or a small number of dispersed droplets. For flexible superhydrophobic bulk materials, the material may be subjected to compression, bending, vibration, or repeated deformation during actual use. The relative distance between multiple droplets changes with material deformation, and the droplets may gradually transform from an initially independent, dispersed state to a closer, bridged, or even continuous liquid path state. This type of deformation-induced multi-droplet connectivity behavior is difficult to effectively identify using traditional static single-droplet contact angle testing.

[0004] Especially in applications such as electrical insulation, anti-flashover, anti-condensation, and outdoor protection, the material surface often contains not only a single pure water droplet, but also raindrops, condensation droplets, salt solution droplets, dirt droplets, or droplets containing particulate contaminants. When flexible superhydrophobic bulk materials deform, if adjacent droplets form liquid bridges and further develop into continuous liquid channels, it may lead to an expansion of the local wetting area, an increase in liquid residue, and the formation of continuous aqueous channels on the surface, thereby weakening the dynamic water-repellent stability of the material. Therefore, relying solely on static water contact angles and roll-off angles to evaluate the water-repellent performance of flexible superhydrophobic bulk materials is insufficient to fully reflect their risk of wetting connectivity failure under actual stress and service conditions.

[0005] Furthermore, existing mechanical testing devices are mostly used to measure the tensile strength, compressive modulus, flexural properties, or cyclic fatigue properties of materials. Their focus is on obtaining mechanical parameters, rather than observing the migration, approach, bridging, and residual liquid behavior of surface droplets during material deformation. While existing contact angle testing equipment can acquire droplet profile and contact angle information, it typically lacks a structure that matches the deformation loading process for sample fixation, synchronous loading, droplet array generation, and multi-view image acquisition. This makes it difficult to simultaneously acquire deformation parameters, droplet array images, liquid bridge formation status, and residual liquid status after unloading and recovery under the same testing sequence. Therefore, existing devices and methods struggle to achieve in-situ observation and quantitative evaluation of the multi-droplet bridging behavior of flexible superhydrophobic bulk materials under controlled deformation conditions.

[0006] Currently, there is a lack of unified evaluation indicators for the deformation-induced droplet bridging behavior of flexible superhydrophobic bulk materials. Traditional wetting tests typically use water contact angle, roll-off angle, or droplet residue as evaluation criteria, but these indicators are difficult to characterize the deformation conditions corresponding to the first bridging of adjacent droplets, and also difficult to quantitatively describe the degree of continuous liquid path formation, liquid bridge unloading and breakage, and liquid residue level. Therefore, it is necessary to establish indicators such as critical bridging deformation parameters, liquid path connectivity, liquid bridge breakage rate, and liquid residue rate that correspond to the deformation loading process, in order to more accurately evaluate the dynamic water-repellent stability of flexible superhydrophobic bulk materials under deformation conditions.

[0007] In summary, the existing technologies have at least the following shortcomings: First, existing static single-droplet wetting tests are insufficient to reflect the multi-droplet bridging behavior of flexible superhydrophobic bulk materials under deformation conditions; second, existing mechanical loading devices and wetting test devices lack effective integration, making it difficult to simultaneously obtain deformation parameters and droplet connectivity; third, existing testing methods lack quantitative evaluation indicators for droplet bridging, continuous liquid path formation, and unloading residues; and fourth, existing tests typically do not fully consider the deformation-induced wetting connectivity risks under complex aqueous droplet conditions such as salt solutions and artificial contaminants. Summary of the Invention

[0008] In view of this, the present invention proposes a flexible material deformation-induced droplet bridging test device, which aims to solve the problem in the prior art that it is difficult to conduct in-situ observation and evaluation of multi-droplet bridging behavior under deformation conditions.

[0009] This invention proposes a flexible material deformation-induced droplet bridging test device, comprising: a base support mechanism for providing a support base; a sample fixing mechanism disposed on the base support mechanism for fixing the end or edge region of the flexible material to be tested, thereby exposing the middle part of the flexible material to be tested to form an open test area; a deformation loading mechanism disposed on the base support mechanism and connected to the sample fixing mechanism for applying compression, tension, bending, or cyclic deformation to the flexible material to be tested; a droplet array generation mechanism disposed above the sample fixing mechanism for forming multiple test droplets spaced apart in a preset array on the surface of the flexible material to be tested in the open test area; an image acquisition mechanism disposed on the base support mechanism for acquiring the droplet behavior characteristics of the test droplets during deformation loading and unloading processes; and a data processing mechanism electrically connected to the image acquisition mechanism and the deformation loading mechanism, for analyzing the behavior of the test droplets during deformation and unloading processes based on the image data acquired by the image acquisition mechanism and the deformation loading data of the deformation loading mechanism, in order to evaluate its ability to maintain a multi-droplet dispersion state under deformation conditions.

[0010] Furthermore, in the above-mentioned flexible material deformation-induced droplet bridging test device, the sample fixing mechanism includes: a fixed clamping member for clamping one end of the flexible material to be tested; and a movable clamping member disposed on one side of the fixed clamping member in a manner opposite to the fixed clamping member, wherein the movable clamping member can move toward or away from the fixed clamping member to clamp the other end of the flexible material to be tested and to cause the flexible material to be tested to undergo compression or tensile deformation.

[0011] Furthermore, in the above-mentioned flexible material deformation-induced droplet bridging test device, the clamping end of the fixed clamping member and / or the movable clamping member is provided with a flexible protective clip for clamping and protecting the flexible material to be tested.

[0012] Furthermore, in the aforementioned flexible material deformation-induced droplet bridging test device, the deformation loading mechanism includes: a moving drive member, the power output end of which is connected to the moving clamping member, for driving the moving clamping member to move towards or away from the fixed clamping member to apply tension, bending, or cyclic deformation to the flexible material under test; and a bending support member, disposed below the sample fixing mechanism, having an arc-shaped support surface, for contacting and engaging with the lower surface of the flexible material under test during bending testing, so that the flexible material under test bends under the drive of the moving clamping member and forms a preset bending radius or bending curvature.

[0013] Furthermore, in the aforementioned flexible material deformation-induced droplet bridging test device, the droplet array generation mechanism is any one of a micro-syringe, a multi-channel dispensing head, an array dispensing template, or an automatic dispensing unit. By controlling the dispensing position, dispensing volume, and dispensing quantity, test droplet arrays with different array forms and / or different droplet parameters are formed on the test surface; the preset array form is any one of a linear array, a rectangular array, a ring array, or a gradient spacing array.

[0014] Furthermore, in the aforementioned flexible material deformation-induced droplet bridging test device, the image acquisition includes: a light source for emitting light to enhance the image contrast of the droplet boundary, the neck of the liquid bridge, and the liquid residue area; a top-view image acquisition unit for acquiring the planar position change, droplet center distance change, liquid bridge formation, and continuous liquid path formation of the test droplet during the deformation process; a side-view image acquisition unit for acquiring the outline morphology, spreading state, contact state, and liquid residue state after unloading and recovery of the test droplet; a calibration ruler for spatially calibrating the image pixel size; and a trigger acquisition unit for triggering the top-view and side-view image acquisition units to acquire images when the flexible material under test reaches a preset deformation amount, a preset loading time, or a preset number of loading cycles.

[0015] Furthermore, the aforementioned flexible material deformation-induced droplet bridging test device further includes: a synchronization control mechanism, which is electrically connected to the droplet array generation mechanism, the deformation loading mechanism, and the image acquisition mechanism, respectively, for controlling the deformation loading parameters, droplet arrangement parameters, and image acquisition time to be within the same test sequence.

[0016] Furthermore, the aforementioned flexible material deformation-induced droplet bridging test device analyzes and calculates the image recognition data acquired by the image acquisition mechanism and the deformation loading data of the deformation loading mechanism to evaluate its ability to maintain a multi-droplet dispersed water-repellent state under deformation conditions. Specifically, if no droplet bridging occurs within a preset deformation range or if droplet bridging occurs but no continuous liquid path is formed, and the droplets redisperse after unloading and the residual liquid coverage area is less than a preset threshold, then the dynamic water-repellent stability of the flexible material under test is deemed qualified. If droplet bridging occurs within a preset deformation range and a continuous liquid path connecting adjacent droplets is formed, or if the residual liquid coverage area after unloading is greater than or equal to a preset threshold, then the material is deemed to have a risk of deformation-induced wetting and interconnection.

[0017] Furthermore, in the aforementioned flexible material deformation-induced droplet bridging test device, the analysis and calculation based on the image recognition data acquired by the image acquisition mechanism and the deformation loading data of the deformation loading mechanism to evaluate its ability to maintain a multi-droplet dispersed water-repellent state under deformation conditions specifically involves: analyzing and calculating based on the image recognition data acquired by the image acquisition mechanism and the deformation loading data of the deformation loading mechanism to confirm the dynamic water-repellent parameters of the flexible material under test, thereby evaluating its ability to maintain a multi-droplet dispersed water-repellent state under deformation conditions.

[0018] Furthermore, in the aforementioned flexible material deformation-induced droplet bridging test device, the dynamic water-repellent parameters of the flexible superhydrophobic block material include: critical bridging deformation parameters, liquid path connectivity, liquid bridge breakage rate after unloading and recovery, and liquid residue rate; wherein, the critical bridging deformation parameters are the compression rate, tensile rate, bending curvature, or number of cyclic loading cycles corresponding to the first occurrence of droplet bridging.

[0019] The flexible material deformation-induced droplet bridging testing device provided by this invention exposes the middle part of the flexible material under test to form an open testing area through a sample fixing mechanism, providing a clear testing window for droplet generation and image acquisition. A deformation loading mechanism applies compression, tension, bending, or cyclic deformation to the flexible material under test within the open testing area, achieving controlled deformation loading. A droplet array generation mechanism generates multiple spaced test droplets in a preset array within the open testing area, providing a controllable test object for observing multi-droplet bridging behavior. An image acquisition mechanism collects the droplet behavior characteristics during deformation loading and unloading, achieving visual recording of droplet behavior. A data processing mechanism performs correlation analysis based on image data and deformation loading data, establishing a correspondence between deformation parameters and droplet behavior. The aforementioned mechanisms work in concert to integrate deformation loading, droplet array generation, image acquisition, and data processing into a single system. This allows for the simultaneous acquisition of deformation parameters, droplet array changes, and droplet bridging states of the flexible material under test within the same testing sequence. This effectively solves the problem in existing technologies where the lack of an integrated structure matching the deformation loading process for sample fixation, deformation loading, droplet array generation, and image acquisition makes it difficult to simultaneously acquire deformation parameters and droplet behavior states within the same testing sequence, thus hindering in-situ observation and evaluation of multi-droplet bridging behavior under deformation conditions. This solution addresses the challenge of in-situ observation and evaluation of multi-droplet bridging behavior under deformation conditions, rather than simply performing static contact angle tests on materials. It constructs a comprehensive testing scheme integrating deformation loading, droplet array generation, synchronous image acquisition, bridging recognition, data processing, and result evaluation to address the potential issues of multi-droplet migration, approach, bridging, continuous liquid path formation, and post-unloading liquid residue in flexible superhydrophobic bulk materials during compression, tension, bending, or cyclic deformation.

[0020] Furthermore, by setting up an open test area, the device ensures that the central droplet test area is not obstructed by the fixture while the flexible material under test is being clamped and loaded. This enables in-situ synchronous acquisition of droplet array arrangement, top view image acquisition, and side view image acquisition, improving the observability and repeatability of deformation wetting tests. By using multiple spaced test droplets as test objects, the device can observe the transformation process of droplets from a dispersed state to migration, approach, bridging, continuous liquid path, and unloading residual state, thereby identifying deformation-induced wetting connectivity risks that are difficult to detect with traditional contact angle and roll-off angle tests.

[0021] Furthermore, this device can calculate evaluation indicators such as critical bridging deformation parameters, droplet center distance change rate, liquid path connectivity, liquid bridge breakage rate, and liquid residue rate, transforming droplet bridging behavior from qualitative observation to calculable, comparable, and repeatable quantitative evaluation results. Simultaneously, the test droplets include not only standard aqueous phase droplets such as deionized water, but also environmental simulated droplets such as salt solution droplets, artificially contaminated droplets, dyed droplets, acidic simulated rainwater droplets, and alkaline simulated droplets. This allows for the simulation of the actual service environment of flexible materials under rainwater, salt spray, condensation, contamination deposition, and complex aqueous pollution conditions, improving the engineering applicability of the testing method. This invention is applicable to the dynamic water-repellent stability evaluation of flexible superhydrophobic bulk materials, flexible insulating and protective materials, anti-fouling flashover water-repellent materials, anti-condensation materials, and porous elastic hydrophobic bulk materials, providing testing basis for material formulation screening, structural optimization, durability evaluation, and risk assessment before engineering applications. Attached Figure Description

[0022] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a schematic diagram of the structure of the flexible material deformation-induced droplet bridging test device provided in an embodiment of the present invention; Figure 2 This is a front view of the flexible material deformation-induced droplet bridging test device provided in an embodiment of the present invention; Figure 3 This is a side view of the test area in the flexible material deformation-induced droplet bridging test device provided in an embodiment of the present invention; Figure 4 This is a top view of the test area in the flexible material deformation-induced droplet bridging test device provided in an embodiment of the present invention; Figure 5 A schematic diagram of a data processing mechanism provided in an embodiment of the present invention; Figure 6 A schematic diagram of the synchronization control mechanism provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the droplet migration, approach, and bridging states of the flexible superhydrophobic bulk material under different compression ratios in Embodiment 1 of the present invention. Figure 8 The curves showing the change in the degree of fluid connectivity of the flexible superhydrophobic bulk material under different compression ratios in Example 1 of this invention are shown. Figure 9 This is a schematic diagram of the liquid bridge fracture and liquid residue state after unloading and recovery of the flexible superhydrophobic block material under test in Embodiment 1 of the present invention; Figure 10 This is a comparison chart of the droplet bridging test results of Examples 1, 2 and various comparative examples in this invention; Explanation of reference numerals in the attached figures: 1-Base support mechanism, 11-Base plate, 12-Guide structure, 2-Sample fixing mechanism, 21-Fixed clamping component, 22-Moving clamping component, 3-Deformation loading mechanism, 31-Moving drive component, 4-Droplet array generation mechanism, 5-Image acquisition mechanism, 51-Light source, 52-Top view image acquisition component, 53-Side view image acquisition component, 54-Calibration scale, 6-Data processing mechanism, 7-Flexible material under test, 71-Open test area, 8-Test droplet, 81-Continuous liquid path, 82-Liquid residue area, 9-Synchronization control mechanism. Detailed Implementation

[0023] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] See Figures 1 to 4 The figure illustrates a preferred structure of the flexible material deformation-induced droplet bridging test device provided in an embodiment of the present invention. As shown in the figure, the flexible material deformation-induced droplet bridging test device includes: a base support mechanism 1, a sample fixing mechanism 2, a deformation loading mechanism 3, a droplet array generation mechanism 4, an image acquisition mechanism 5, and a data processing mechanism 6.

[0025] The base support mechanism 1 is used to provide a support base to provide support.

[0026] Specifically, the base support mechanism 1 provides a stable mounting foundation for the entire device to support the entire testing apparatus. It can be a flat plate structure or a frame structure made of metal. The upper surface of the base support mechanism 1 provides a mounting plane for each functional mechanism, ensuring the relative positional accuracy between the mechanisms.

[0027] The sample fixing mechanism 2 is set on the base support mechanism 1 and is used to fix the end or edge area of ​​the flexible material to be tested, so that the middle part of the flexible material to be tested 7 is exposed to form an open test area 71.

[0028] Specifically, the sample fixing mechanism 2 is mounted on the base support mechanism 1, and the sample fixing mechanism 2 holds the opposite sides of the flexible material 7 to be tested (e.g., Figure 1 The droplets are clamped and fixed on both sides (as shown) to expose the middle area, so as to facilitate the observation of droplet behavior during subsequent droplet addition and deformation loading.

[0029] The deformation loading mechanism 3 is mounted on the base support mechanism 1 and connected to the sample fixing mechanism 2, and is used to apply compression, tension, bending or cyclic deformation to the flexible material 7 to be tested.

[0030] Specifically, the deformation loading mechanism 3 is connected to the movable part of the sample fixing mechanism 2. By driving the movable part of the sample fixing mechanism 2 to move, the flexible material 7 to be tested undergoes a preset type of deformation. The deformation loading mechanism 3 is also equipped with a displacement sensor and a force sensor to collect displacement and load data in real time during the deformation loading process and transmit them to the data processing mechanism 6. Of course, in this embodiment, the base support mechanism 1 may also be equipped with a displacement scale to assist in reading the compression displacement or tensile displacement.

[0031] The droplet array generation mechanism 4 is positioned above the sample fixing mechanism 2 and is used to form multiple spaced test droplets 8 in a preset array pattern on the surface of the flexible material 7 to be tested in the open test area 71.

[0032] Specifically, the droplet array generation mechanism 4 is positioned above the open testing area 71. By controlling the droplet position, droplet volume, and droplet quantity, a test droplet array 8 in a preset array form can be formed within the open testing area 71. The preset array form can be a linear array, a rectangular array, a ring array, or a gradient spacing array. The number of test droplets 8 is 2-50, the volume of a single test droplet 8 is 1-50 μL, and the initial center-to-center distance between adjacent test droplets 8 is 1-30 mm. In this embodiment, the test droplets 8 can be standard aqueous phase droplets or environmental simulation droplets. Standard aqueous phase droplets include deionized water droplets, and environmental simulation droplets include one or more of the following: salt solution droplets, artificial dirt droplets, dye droplets, acidic simulated rainwater droplets, or alkaline simulated droplets. The surface tension of the test droplets 8 is 30-75 mN / m, the viscosity is 0.8-10 mPa·s, and the conductivity is 1 μS / cm-80 mS / cm. Among them, deionized water droplets can be used as the benchmark test droplets 8 to eliminate the influence of complex ionic and particulate contamination factors on the test results; salt solution droplets, artificial dirt droplets, and acidic simulated rainwater droplets can be used to simulate droplet bridging behavior under rainwater, salt spray, condensation, dirt deposition, and complex aquatic pollution environments. Artificial dirt droplets include an aqueous base solution, soluble salts, solid dirt particles, and a colorimetric agent. Specifically, the aqueous base solution is one of deionized water, tap water, simulated rainwater solution, or simulated condensation solution; the soluble salt is one or more of sodium chloride, potassium chloride, sodium sulfate, or sodium nitrate, with a mass fraction of 0.1%-5%; the solid dirt particles are one or more of kaolin, silica, diatomaceous earth, alumina powder, or calcium carbonate powder, with a mass fraction of 0.05%-2%; and the colorimetric agent is one or more of methylene blue, rhodamine B, sodium fluorescein, or food-grade dyes, with a mass fraction of 0.001%-0.05%. By conducting droplet bridging tests in the aforementioned different liquid systems, the dynamic water-repellent stability of the flexible material 7 under test can be comprehensively evaluated in complex aqueous environments, making it closer to actual application conditions. In a single test, multiple test droplets 8 use the same test liquid. Different test liquids correspond to different test groups, used to compare the deformation-induced bridging risk under different liquid conditions.

[0033] The image acquisition mechanism 5 is mounted on the base support mechanism 1 and is used to acquire the droplet behavior characteristics of the test droplet 8 during the deformation loading and unloading process.

[0034] Specifically, the image acquisition mechanism 5 is used to acquire images of the test droplet 8 within the open test area 71 to record the behavioral characteristics of the test droplet 8 during the entire process of deformation and unloading recovery of the flexible material 7 under test. The droplet behavioral characteristics include at least the changes in the planar position of the test droplet 8 during deformation loading and unloading, changes in the droplet center distance, the formation state of liquid bridges, the formation state of continuous liquid paths 81, the contour morphology, the spreading state, the contact state, and the residual liquid state after unloading recovery. The image acquisition mechanism 5 continuously acquires images at a preset sampling frequency during the deformation loading process to ensure that the droplet behavior is completely recorded throughout the entire deformation loading process, without missing any key evolutionary nodes from dispersion to approach, contact, bridging, and the formation of continuous liquid paths 81. The image acquisition mechanism 5 is electrically connected to the data processing mechanism 6 and transmits the acquired image data to the data processing mechanism 6 in real time for subsequent analysis and processing.

[0035] The data processing unit 6 is electrically connected to the image acquisition unit 5 and the deformation loading unit 3, respectively. It is used to analyze the behavior of the test droplet 8 during the deformation and unloading process based on the image data acquired by the image acquisition unit 5 and the deformation loading data of the deformation loading unit 3, so as to evaluate its ability to maintain the multi-droplet dispersion state under deformation conditions.

[0036] Specifically, the data processing unit 6 synchronously receives deformation loading data collected in real time by the deformation loading unit 3 and image data collected in real time by the image acquisition unit 5. The data processing unit 6 establishes a correspondence between deformation parameters and droplet behavior by synchronizing the image data and deformation loading data along the time axis, thus determining the position distribution, spacing changes, contact state, and morphological evolution of each test droplet 8 under each deformation. Based on this correspondence, the data processing unit 6 outputs the analysis results of droplet behavior in the image data, allowing testers to assess the ability of the flexible material 7 under controlled deformation to maintain a multi-droplet dispersed water-repellent state, and to evaluate the risk of droplet bridging, continuous liquid path 81 formation, and liquid residue after unloading under deformation-induced conditions. The deformation loading data can be displacement, load, loading time, or number of cycles.

[0037] In this embodiment, the device may further include a synchronization control mechanism 9; wherein the synchronization control mechanism 9 is electrically connected to the droplet array generation mechanism 4, the deformation loading mechanism 3, and the image acquisition mechanism 5 respectively, and is used to control the deformation loading parameters, droplet arrangement parameters and image acquisition time to be within the same test sequence.

[0038] Specifically, during the test, the synchronous control mechanism 9 sends a loading command to the deformation loading mechanism 3, controlling it to apply deformation to the flexible material 7 under test according to a preset loading rate and target deformation. Simultaneously, it sends a dotting command to the droplet array generation mechanism 4, controlling it to generate test droplets 8 on the surface of the flexible material 7 under test according to a preset array pattern, droplet volume, and dotting position. At the same time, it sends a collection command to the image acquisition mechanism 5, controlling it to trigger image acquisition at a preset collection time, so that it can acquire droplet images in the same time series and establish the correspondence between deformation parameters and droplet bridging states. Through the unified timing scheduling of the synchronous control mechanism 9, the three processes of deformation loading, droplet generation, and image acquisition are precisely aligned on the time axis. That is, the trigger time of image acquisition matches the start time, loading rate, and droplet generation completion time of deformation loading, avoiding time misalignment between the deformation process and the droplet generation and image acquisition processes, ensuring that the acquired image data accurately reflects the real behavior of the test droplet 8 under a specific deformation state. In addition, the synchronous control mechanism 9 can also record the loading time and real-time deformation parameters, and associate and store the above data with the image data collected at the corresponding time, thereby establishing a precise correspondence between the deformation loading parameters and the droplet behavior, providing a time-consistent basic data for subsequent data analysis.

[0039] See also Figure 1 The base support mechanism 1 may include a base plate 11 and a support frame (not shown in the figure) disposed on the base plate 11. The support frame is used to install the droplet array generation mechanism 4 and the image acquisition mechanism 5.

[0040] Specifically, the base plate 11 can be a flat plate structure, which can be placed horizontally on the test platform as the mounting base for the entire device, supporting various functional components such as the sample fixing mechanism 2 and the deformation loading mechanism 3. The base plate 11 may have mounting holes or positioning slots to facilitate precise installation and position adjustment of each mechanism. A support frame is fixedly mounted on the base plate 11, extending vertically upwards, with its top extending above the sample fixing mechanism 2, for mounting the droplet array generation mechanism 4 and the image acquisition mechanism 5. By mounting the droplet array generation mechanism 4 and the image acquisition mechanism 5 on the same support frame, the relative positional accuracy between them and the flexible material 7 under test is ensured, guaranteeing that the test droplet 8 can be accurately positioned within the preset location in the open test area 71, while simultaneously ensuring that the image acquisition mechanism 5 has a stable imaging field of view and fixed imaging parameters. In this embodiment, the base plate 11 may also be provided with a guide structure 12, such as a guide rail or guide groove, for guiding and constraining the movement direction of the deformation loading mechanism 3, especially for guiding and constraining the movement direction of the moving clamp 22 of the sample fixing mechanism 2, to ensure that the deformation loading direction is consistent with the preset direction and improve the repeatability of the test. The base plate 11 may also be provided with a displacement scale for assisting in reading and calibrating the displacement of the deformation loading.

[0041] See also Figure 1 The sample fixing mechanism 2 includes a fixed clamping member 21 and a movable clamping member 22. The fixed clamping member 21 is used to clamp one end of the flexible material 7 to be tested. The movable clamping member 22 is arranged opposite to the fixed clamping member 21 on one side of the fixed clamping member 21. The movable clamping member 22 can move towards or away from the fixed clamping member 21 to clamp the other end of the flexible material 7 to be tested and to cause the flexible material 7 to undergo compression or stretching deformation.

[0042] Specifically, the fixed clamp 21 is fixedly mounted on the base support mechanism 1 and remains stationary, particularly on the left side of the base support mechanism 1; the movable clamp 22 is slidably mounted on the base support mechanism 1, located to the right of the fixed clamp 21 and arranged opposite to it. The fixed clamp 21 and the movable clamp 22 respectively clamp the two ends or the two side edge regions of the flexible material 7 to be tested, leaving the middle of the flexible material 7 exposed, forming an open test area 71. When performing a compression test, the movable clamp 22, driven by the deformation loading mechanism 3, moves towards the fixed clamp 21 (e.g., ...). Figure 1 Move to the left (as shown), so that the flexible material 7 to be tested moves along its length (e.g., to the left). Figure 1 The horizontal direction shown is compressed; when a tensile test is performed, the movable clamp 22 is driven by the deformation loading mechanism 3 to move away from the fixed clamp 21 (as shown in the image). Figure 1The flexible material 7 under test is stretched along its length by moving to the right (as shown). Through the cooperation of the fixed clamp 21 and the movable clamp 22, the flexible material 7 under test maintains a stable clamping state during deformation loading, ensuring that the deformation is concentrated within the open test area 71. This facilitates the droplet array generation mechanism 4 in arranging test droplets 8 within the open test area 71, and the image acquisition mechanism 5 in observing the droplet behavior. In this embodiment, the bottom of the movable clamp 22 can be adapted to the guide structure 12. The movable clamp 22 can only move along the direction defined by the guide structure 12, thereby ensuring that the flexible material 7 under test has a definite deformation direction during deformation loading. This avoids deviation of the deformation direction from the preset direction due to skewness of the movable clamp 22 during movement, which would affect the accuracy and repeatability of the test results. Simultaneously, the movable clamping member 22 is connected to the power output end of the deformation loading mechanism 3. The driving force generated by the deformation loading mechanism 3 is transmitted to the movable clamping member 22 through its power output end, driving the movable clamping member 22 to move along the guide structure 12 towards or away from the fixed clamping member 21, thereby applying compression or tensile deformation to the flexible material 7 to be tested, which is clamped between the fixed clamping member 21 and the movable clamping member 22. By adapting the bottom of the movable clamping member 22 to the guide structure 12 and connecting the movable clamping member 22 to the power output end of the deformation loading mechanism 3, the power output by the deformation loading mechanism 3 can be accurately and stably transmitted to the flexible material 7 to be tested, avoiding deviation in the loading direction caused by transmission gaps or movement skew, and ensuring the accuracy of deformation loading and the reliability of test data.

[0043] In this embodiment, the clamping ends of the fixed clamping member 21 and / or the movable clamping member 22 are provided with flexible protective clips for clamping and protecting the flexible material 7 to be tested. Specifically, the flexible protective clips are respectively disposed on the inner clamping surfaces of the fixed clamping member 21 and the movable clamping member 22, and are located between the fixed clamping member 21, the movable clamping member 22 and the edge area of ​​the flexible material 7 to be tested. The fixed clamping member 21 and the movable clamping member 22 clamp the two ends or edge areas of the flexible material 7 to be tested through the flexible protective clips, keeping the middle part of the flexible material 7 to be tested exposed, forming an open test area 71. The flexible protective clips can be one of silicone pads, rubber pads, polytetrafluoroethylene sheets or other low-damage flexible clamping pieces. During clamping, the flexible protective clip directly contacts the surface of the flexible material 7 under test. Utilizing its flexibility and elastic deformation capabilities, it effectively buffers the clamping force, reducing damage to the micro-nano water-repellent structure on the surface of the flexible material 7 during clamping. This prevents the clamping end from causing indentations, scratches, or damage to the surface microstructure of the flexible material 7, thus ensuring that the test results accurately reflect the inherent water-repellent properties of the flexible material 7. Simultaneously, the flexible protective clip 23 also increases clamping friction, reducing slippage and localized stress concentration, preventing slippage of the flexible material 7 during deformation loading, and ensuring the stability of deformation loading and the reliability of test data. In this embodiment, the flexible protective clip is detachably installed, facilitating replacement after wear and ensuring the continuity of the clamping protection effect.

[0044] In this embodiment, the deformation loading mechanism 3 includes a moving drive member 31 and a bending support member (not shown in the figure); wherein, the power output end of the moving drive member 31 is connected to the moving clamp member 22, and is used to drive the moving clamp member 22 to move towards or away from the fixed clamp member 21 to apply tension, bending or cyclic deformation to the flexible material 7 to be tested; the bending support member is disposed below the sample fixing mechanism 2 and has an arc-shaped support surface, which is used to contact and cooperate with the lower surface of the flexible material 7 to be tested during the bending test, so that the flexible material 7 to be tested bends under the drive of the moving clamp member 22 and forms a preset bending radius or bending curvature.

[0045] Specifically, the moving drive component 31 can be one of a lead screw loading assembly, an electric push rod loading assembly, or a universal testing machine connection assembly. Taking the lead screw loading assembly as an example, it includes a drive motor, a lead screw, and a lead screw nut. The lead screw is rotatably mounted on the base support mechanism 1, and the lead screw nut is fixedly connected to the moving clamping component 22. When the drive motor drives the lead screw to rotate, the lead screw nut drives the moving clamping component 22 to move along the lead screw axis. The moving drive component 31 is also equipped with a displacement sensor and a force sensor to collect displacement data and load data in real time during the deformation loading process and transmit them to the data processing mechanism 6. The bending support component is located below the open test area 71, between the fixed clamping component 21 and the moving clamping component 22. The curved support surface of the bending support component faces upward, and the radius of curvature of this curved support surface can be replaced or adjusted according to the test requirements.

[0046] During compression testing, the moving drive component 31 drives the moving clamping component 22 to move towards the fixed clamping component 21, compressing the flexible material 7 under test along its length. At this time, the bending support component is in an avoidance position or removed from the test area and does not participate in the test. During tensile testing, the moving drive component 31 drives the moving clamping component 22 to move away from the fixed clamping component 21, stretching the flexible material 7 under test along its length. During bending testing, the bending support component is positioned below the open test area 71, with its arc-shaped support surface contacting the lower surface of the flexible material 7 under test. When the moving drive component 31 drives the moving clamping component 22 towards the fixed clamping component 21, the flexible material 7 under test bends under the combined constraint of the clamping at both ends and the arc-shaped support surface in the middle, forming a bending radius or bending curvature corresponding to the curvature of the arc-shaped support surface. By replacing the bending support component with different radii of curvature, tests for different degrees of bending can be performed. When performing cyclic deformation tests, the moving drive component 31 drives the moving clamp component 22 to reciprocate according to the preset loading frequency and number of loading cycles, applying repeated compression-recovery, tension-recovery or bending-recovery cyclic loads to the flexible material 7 under test.

[0047] In this embodiment, the droplet array generation mechanism 4 can be any one of a micro-syringe, a multi-channel dispensing head, an array dispensing template, or an automatic dispensing unit. Specifically, the droplet array generation mechanism 4 can form arrays of test droplets 8 with different array forms and / or different droplet parameters on the surface of the flexible material 7 under test within the open test area 71 by controlling the dispensing position, dispensing volume, and dispensing quantity. The dispensing position determines the distribution position of each test droplet 8 on the surface of the flexible material 7 under test; different array forms can be formed by setting different dispensing coordinates. The dispensing volume determines the size of a single test droplet 8; different volumes of droplets can be generated by controlling the amount dispensed each time. The dispensing quantity determines the total number of test droplets 8; different sizes of droplet arrays can be formed by setting the number of dispensing times. These three factors work together to determine the final shape and parameters of the test droplet 8 array. The array form includes, but is not limited to, any one of a linear array, rectangular array, ring array, or gradient spacing array; the droplet parameters include droplet volume and droplet spacing, etc. Through the above control, the arrangement of the droplet array can be flexibly adjusted according to the test objective within the same test to adapt to different test requirements. For example, a linear array can be used to evaluate the variation of droplet spacing with deformation in a single direction; a rectangular or ring array can be used to evaluate the anisotropy of droplet bridging behavior in multiple directions; and a gradient spacing array can be used to simultaneously evaluate the bridging tendency of droplets under different initial spacings in a single test, improving test efficiency. For example, test droplet 8 is arranged in a gradient spacing array, so that the initial center distance between adjacent droplets along the loading direction gradually increases from 2 mm to 10 mm, and the initial center distance perpendicular to the loading direction is 5 mm, to compare the critical bridging deformation parameters under different initial droplet spacings. This method can determine the bridging sensitivity of the flexible superhydrophobic bulk material under test under different droplet spacing conditions.

[0048] See also Figure 1 The image acquisition mechanism 5 includes: a light source 51, a top view image acquisition unit 52, a side view image acquisition unit 53, a calibration ruler 54, and a trigger acquisition unit (not shown in the figure).

[0049] Light source 51 is used to emit light to enhance the image contrast of the droplet boundary, liquid bridge neck, and liquid residue area 82. Specifically, light source 51 is positioned above both sides of the open test area 71, and can be mounted on a support to provide uniform and clear illumination for image acquisition. Light source 51 can be one or more of a ring light source 51, a strip light source 51, a backlight source 51, or a coaxial light source 51. The supplementary illumination from light source 51 enhances the image contrast between the boundary contour of the test droplet 8, the liquid bridge neck, and the liquid residue area 82 after unloading, and the surface of the flexible material 7 under test, facilitating accurate identification of the droplet contour and accurate extraction of the droplet boundary in subsequent image processing and analysis. In this embodiment, two light sources 51 are used, respectively positioned on both sides of the top-view image acquisition unit 52.

[0050] The top-view image acquisition unit 52 is used to acquire the planar position changes, droplet center-to-center distance changes, liquid bridge formation, and continuous liquid path 81 formation of the test droplet 8 during the deformation process. Specifically, the top-view image acquisition unit 52 is supported by a bracket directly above the open test area 71, with its optical axis perpendicular to the surface of the flexible material 7 under test. During the deformation loading and unloading process, the top-view image acquisition unit 52 continuously acquires planar images of the test droplets 8 from a top-view angle to identify the planar position changes of each test droplet 8 during the deformation process, the center-to-center distance changes between adjacent droplets, the liquid bridge formation area, and the formation of continuous liquid paths 81 connecting adjacent droplets, providing image data for planar analysis of droplet bridging behavior.

[0051] The side-view image acquisition unit 53 is used to acquire the contour morphology, spreading state, contact state, and residual liquid state after unloading and recovery of the test droplet 8. Specifically, the side-view image acquisition unit 53 is located on the side of the open test area 71, with its optical axis parallel to the surface of the flexible material 7 under test. During deformation loading and unloading, the side-view image acquisition unit 53 continuously acquires side images of the test droplet 8 from a side-view angle to observe the contour morphology of the test droplet 8, the spreading state of the droplet on the surface of the flexible material 7 under test, the contact state between the droplet and the material surface, and the state of the residual liquid area on the material surface after unloading and recovery, providing image data for the side-view analysis of droplet wetting behavior. The top-view image acquisition unit 52 and the side-view image acquisition unit 53 perform synchronous image acquisition under the control of the trigger acquisition unit to ensure the temporal consistency of the top view and the side view at the same time.

[0052] The calibration ruler 54 is used for spatial calibration of image pixel dimensions. Specifically, the calibration ruler 54 is located near the open test area 71, within the common field of view of the top-view image acquisition unit 52 and the side-view image acquisition unit 53, and can be fixed to the base plate 11. The calibration ruler 54 has scale marks of known size for calibrating the pixel dimensions of the acquired image. By identifying pixels through the scale marks on the calibration ruler 54 in the acquired image, the pixel distance in the image can be converted into actual physical distance, realizing spatial calibration of image data, thereby ensuring the accuracy of measurement of geometric parameters such as droplet center distance, droplet size, and liquid bridge width.

[0053] The trigger acquisition unit is used to trigger the top-view image acquisition unit 52 and the side-view image acquisition unit 53 to acquire images when the flexible material 7 under test reaches a preset deformation, preset loading time, or preset number of loading cycles. Specifically, the trigger acquisition unit is electrically connected to the deformation loading mechanism 3, the top-view image acquisition unit 52, and the side-view image acquisition unit 53, respectively. During the test, the trigger acquisition unit monitors the deformation loading data of the deformation loading mechanism 3 in real time. When the monitored deformation loading data reaches the preset trigger condition, the trigger acquisition unit sends a trigger signal to the top-view image acquisition unit 52 and the side-view image acquisition unit 53 simultaneously, so that the two perform synchronous image acquisition at the same time. This ensures that the acquired top-view image and side-view image are strictly corresponding on the time axis, avoiding data correlation deviations caused by inconsistent image acquisition times. Through the control of the trigger acquisition unit, image data of the droplet state can be accurately acquired at key deformation nodes, establishing a precise correspondence between deformation parameters and droplet behavior. The key deformation nodes can be preset compression rate, preset tensile rate, preset bending curvature, or preset number of cycles.

[0054] See Figure 5 The figure shows a schematic diagram of the data processing mechanism 6 provided in an embodiment of the present invention. As shown, the data processing mechanism 6 has a built-in image processing and analysis program, and its processing flow includes: image import, droplet recognition, liquid bridge recognition, continuous liquid path recognition, residual area recognition, parameter calculation, and result output.

[0055] Specifically, image import is the initial step in the data processing flow. The data processing unit 6 receives image data acquired by the top-view image acquisition unit 52 and the side-view image acquisition unit 53 from the image acquisition unit 5, and classifies and stores the image data according to the acquisition time and acquisition angle, establishing a temporal index corresponding to the deformation loading data to ensure that each frame of image can be traced back to the corresponding deformation loading time. Droplet recognition is the first stage of image processing and analysis. The data processing unit 6 preprocesses the imported top-view and side-view images, and then identifies and locates each test droplet 8 in the image based on the droplet contour features, determining the center coordinates, contour boundary, and projected area of ​​each test droplet 8, providing basic data for subsequent droplet spacing calculation and deformation tracking.

[0056] Liquid bridge identification follows droplet identification in the analysis phase. The data processing unit 6 determines whether a liquid bridge exists between adjacent test droplets 8 based on the droplet identification results. When a continuous liquid neck forms a continuous liquid bridge connection region between two adjacent test droplets 8, and this liquid bridge connection region persists for a preset stabilization time, the data processing unit 6 determines that droplet bridging has occurred between the adjacent droplet pair and records the deformation loading parameters corresponding to the formation of the liquid bridge. For example, the compression ratio, elongation ratio, flexural curvature, or number of cyclic loading cycles corresponding to the first occurrence of this state are the critical bridging deformation parameters. The preset stabilization time can be determined based on the image acquisition frame rate and the properties of the test liquid, for example, set to 0.1 s, or set to ensure that the liquid bridge connection region is detected in several consecutive frames of images.

[0057] The continuous liquid path identification is a subsequent analysis stage after the liquid bridge identification. The data processing unit 6 determines, based on the liquid bridge identification results, whether the formed liquid bridge will further develop into a continuous liquid path 81 connecting adjacent droplets. Specifically, when three or more test droplets 8 are sequentially connected through a liquid bridge, the data processing unit 6 determines that a continuous liquid path 81 has been formed and records the deformation loading parameters corresponding to the formation of the continuous liquid path 81. The maximum projected length of the continuous liquid path 81 along a preset evaluation direction is used to calculate the liquid path connectivity. The preset evaluation direction can be the tensile or compressive direction of the flexible material under test.

[0058] The residual area identification is part of the post-unloading and recovery analysis phase. After deformation unloading, the data processing unit 6 processes and analyzes the acquired top and side view images to identify and extract the contour and area of ​​the residual liquid region on the surface of the flexible material 7 under test. Specifically, based on the grayscale characteristics and contour morphology of the residual liquid in the images, the data processing unit 6 distinguishes the residual liquid region from the background region of the material surface and calculates the residual liquid coverage area and its proportion of the initial total coverage area of ​​the test droplets 8 in the open test area 71 before loading, i.e., the liquid residue rate. It can also calculate the liquid bridge breakage rate.

[0059] The parameter calculation is the quantitative analysis stage following the identification results. The data processing unit 6 calculates the dynamic water-repellent parameters of the flexible material 7 under test based on the results of droplet identification, liquid bridge identification, continuous liquid path identification, and residual area identification, combined with the spatial calibration data of the calibration ruler 54. The dynamic water-repellent parameters include: critical bridging deformation parameters (the deformation corresponding to the first bridging of adjacent droplets), liquid path connectivity (the ratio of the maximum projected length of the continuous liquid path 81 along the preset evaluation direction to the effective length of the open test area 71 along that direction under the preset evaluation deformation state), liquid bridge breakage rate (the ratio of the number of liquid bridges that break and separate after deformation unloading to the total number of liquid bridges before unloading), and liquid residue rate (the ratio of the residual liquid coverage area after unloading recovery to the initial total coverage area of ​​the test droplet 8 in the open test area 71 before loading). Among these, the critical bridging deformation parameters are the compression ratio, tensile ratio, bending curvature, or number of cyclic loading cycles corresponding to the first occurrence of droplet bridging.

[0060] The output results are the final step in the data processing process. The data processing unit 6 outputs the analysis results and calculated dynamic water-repellent parameters of each stage in the form of data reports and / or images, so that the test personnel can evaluate the ability of the flexible material 7 under deformation conditions to maintain a multi-droplet dispersion state, and assess the risk of droplet bridging, continuous liquid path 81 formation and liquid residue after unloading under deformation-induced conditions.

[0061] In one embodiment of the data processing mechanism 6 in this example, the image recognition data acquired by the image acquisition mechanism 5 and the deformation loading data of the deformation loading mechanism 3 are analyzed and calculated to evaluate its ability to maintain a multi-droplet dispersed water-repellent state under deformation conditions. Specifically, if no droplet bridging occurs within the preset deformation range or if droplet bridging occurs but no continuous liquid path 81 is formed, and the droplets redisperse after unloading and the residual liquid coverage area is less than the preset threshold, then the dynamic water-repellent stability of the flexible material 7 under test is deemed qualified. If droplet bridging occurs within the preset deformation range and a continuous liquid path 81 connecting adjacent droplets is formed, or if the residual liquid coverage area after unloading is greater than or equal to the preset threshold, then the material is deemed to have a risk of deformation-induced wetting and connectivity.

[0062] Specifically, the data processing unit 6 performs frame-by-frame analysis of droplet behavior throughout the entire deformation loading and unloading process based on the top-view and side-view images acquired in real time by the image acquisition unit 5. During the deformation loading stage, the data processing unit 6 tracks the changes in the center position of each test droplet 8 and the changes in the center distance between adjacent droplets. When the contour boundaries of two adjacent test droplets 8 come into contact or overlap, it is determined that a liquid bridge has been formed between the adjacent droplet pair, and the deformation corresponding to the formation of the liquid bridge is recorded as the critical deformation parameter for the bridging of the droplet pair. After the liquid bridge is formed, the data processing unit 6 continues to track the evolution of the liquid bridge: if the liquid bridge exists only between two adjacent droplets and does not extend to other droplets, it is determined to be a local liquid bridge; if three or more test droplets 8 are connected sequentially through the liquid bridge to form a continuous liquid channel of a certain length, it is determined to have formed a continuous liquid path 81, and the deformation corresponding to the formation of the continuous liquid path 81 is recorded. After deformation and unloading, the data processing unit 6 analyzes the top and side view images to determine whether the previously bridging adjacent droplets have redispersed. Specifically, the bridging droplets separate under surface tension, each reverting to an independent droplet, and the apparent contact angle of each independent droplet is not less than 90% of its initial contact angle. Simultaneously, the data processing unit 6 identifies the residual liquid area, calculates the proportion of the residual liquid coverage area to the total area of ​​the open test area 71, and compares this proportion with a preset threshold. This preset threshold can be 5%, 10%, or 15%, or can be pre-set according to specific test requirements. If no droplet bridging occurs within the preset deformation range, or if droplet bridging occurs but does not further develop into a continuous liquid path 81, and the bridging droplets redisperse after unloading with the residual liquid coverage area below the preset threshold, it indicates that the flexible material 7 under test can effectively maintain the dispersion of droplets under deformation conditions and possesses excellent dynamic water-repellent stability. Conversely, if, within a predetermined deformation range, adjacent droplets bridge and further develop into a continuous liquid path 81 connecting three or more droplets, or if, after deformation unloading, the bridging droplets fail to redisperse and the residual liquid coverage area reaches or exceeds a predetermined threshold, it indicates that the flexible material 7 under test poses a risk of droplet connectivity and liquid residue under deformation conditions, i.e., a risk of deformation-induced wetting connectivity. Through the above-mentioned judgment method, a quantitative and standardized evaluation of the dynamic water-repellent stability of flexible materials under deformation conditions is achieved.

[0063] In another embodiment of the data processing mechanism 6 in this example, the image recognition data acquired by the image acquisition mechanism 5 and the deformation loading data of the deformation loading mechanism 3 are analyzed and calculated to evaluate its ability to maintain a multi-droplet dispersed water-repellent state under deformation conditions. Specifically, the dynamic water-repellent parameters of the flexible material 7 under test are confirmed based on the image recognition data acquired by the image acquisition mechanism 5 and the deformation loading data of the deformation loading mechanism 3, so as to evaluate its ability to maintain a multi-droplet dispersed water-repellent state under deformation conditions.

[0064] Specifically, the data processing unit 6 analyzes the droplet behavior frame-by-frame during the entire deformation loading and unloading process based on the top-view and side-view images acquired in real time by the image acquisition unit 5, combined with the deformation loading data synchronously recorded by the deformation loading unit 3, and calculates the four dynamic water-repellent parameters mentioned above. The critical bridging deformation parameter is the deformation amount corresponding to the first bridging between adjacent test droplets 8 of the flexible material under test 7 during the deformation loading process. The data processing unit 6 tracks the changes in the center position of each test droplet 8 and the changes in the center distance between adjacent droplets during the deformation loading process; when a continuous liquid bridge connection area is formed between two adjacent test droplets 8, and the liquid bridge connection area continues to exist within a preset stable time, the deformation amount corresponding to the deformation loading unit 3 at that moment is recorded, which is the critical bridging deformation parameter of the droplet pair. This parameter reflects the ultimate deformation ability of the material to maintain the isolated and dispersed state of the droplets under deformation conditions. The larger the value, the stronger the anti-wetting and interconnection ability of the material in maintaining the dispersed state of the droplets within a larger deformation range.

[0065] Liquid path connectivity is the ratio of the maximum projected length of the continuous liquid path 81 along the preset evaluation direction to the effective length of the open test area 71 along the preset evaluation direction under the preset evaluation deformation state. The data processing unit 6 identifies the continuous liquid path 81 under the predetermined evaluation deformation state and calculates its maximum projected length along the preset evaluation direction; when comparing different test materials, the same evaluation deformation state should be used. Higher liquid path connectivity indicates that the material is more likely to form a continuous liquid path under deformation conditions, resulting in poorer dynamic water-repellent stability; conversely, lower liquid path connectivity indicates that the material can effectively prevent the continuous connection between droplets under deformation conditions, resulting in better dynamic water-repellent stability.

[0066] The liquid bridge breakage rate is the ratio of the number of liquid bridges that break after deformation unloading to the total number of liquid bridges before unloading. Data processing unit 6 statistically analyzes the total number of liquid bridges existing before deformation unloading and the number of liquid bridges that break after deformation unloading due to material rebound and droplet surface tension, calculating the ratio between the two. A higher liquid bridge breakage rate indicates that the droplets can effectively separate after deformation recovery, and the material has a stronger ability to resist liquid connectivity and residue. A lower liquid bridge breakage rate indicates that the bridging state between droplets is difficult to disentangle after unloading, easily forming persistent liquid pathways or liquid residue, resulting in poor dynamic water-repellent stability.

[0067] The liquid residue rate is the ratio of the liquid coverage area remaining on the surface of the flexible material 7 after deformation unloading to the initial total coverage area of ​​the test droplet 8 in the open test area 71 before loading. After deformation unloading, the data processing unit 6 identifies and extracts the residual liquid area from the top and side view images, and calculates the proportion of the residual liquid coverage area to the initial total coverage area of ​​the test droplet 8 in the open test area 71 before loading. The lower the liquid residue rate, the fewer liquid bridges, liquid films, liquid tails, or diffusion wetting areas formed after unloading recovery, and the stronger the material's ability to suppress liquid residue; the higher the liquid residue rate, the more difficult it is for the droplets to recover to a separated state or to detach from the material surface, posing a risk of wetting and interconnection.

[0068] By evaluating the four dynamic water-repellent parameters mentioned above in a synergistic manner, the dynamic water-repellent stability of the flexible material under deformation conditions can be comprehensively and quantitatively assessed from different dimensions. The critical bridging deformation parameter evaluates the material's resistance to initial bridging, the liquid channel connectivity evaluates the material's resistance to liquid channel penetration, the liquid bridge breakage rate evaluates the material's ability to dissolve liquid bridges, and the liquid residue rate evaluates the material's ability to suppress liquid residue. These parameters complement each other, forming a complete quantitative evaluation system that effectively overcomes the one-sidedness of traditional single-index evaluations. Among them, the critical bridging deformation parameter and liquid channel connectivity are used to characterize the droplet dispersion maintenance performance during the deformation loading stage, while the liquid bridge breakage rate and liquid residue rate are used to characterize the droplet dispersion recovery performance during the deformation unloading stage. All four parameters participate in the overall dynamic water-repellent stability determination.

[0069] In this embodiment, when the deformation is compression along the length direction, the compression ratio is calculated according to the following formula: ; in, For compression ratio, The initial length of the flexible material to be tested. This represents the real-time length during the loading process.

[0070] When the deformation is stretching along the length direction, the elongation rate is calculated according to the following formula: ; in, This represents the elongation.

[0071] When the deformation is bending, the bending curvature is calculated according to the following formula: ; in, For curvature, The radius of curvature is denoted as .

[0072] When three or more test droplets 8 are connected sequentially through a liquid bridge, and the length of the continuous liquid path 81 reaches more than 20% of the characteristic length of the corresponding direction of the test area, it is determined that a continuous liquid path 81 is formed. The liquid path connectivity of the continuous liquid path 81 is calculated according to the following formula: ; in, For fluid connectivity, The length of the continuous liquid path 81 obtained from image recognition. The test area is the characteristic length along the extension direction of the continuous liquid path 81; when the continuous liquid path 81 extends along the loading direction, The length of the test area along the loading direction; After unloading and recovery, the hydraulic bridge breakage rate is calculated according to the following formula: ; in, The liquid bridge fracture rate, This represents the number of broken liquid bridges after unloading and recovery. This represents the total number of liquid bridges formed during the loading process. The liquid bridge breakage rate is not calculated if no liquid bridges are formed during loading.

[0073] Liquid residue rate is calculated using the following formula: ; in, For liquid residue rate, The area of ​​residual liquid obtained from image recognition after unloading and recovery. This represents the initial total coverage area of ​​test droplet 8 within the test area before loading.

[0074] See Figure 6This is a schematic diagram of the synchronization control mechanism 9 provided in this embodiment of the invention. As shown in the figure, the synchronization control mechanism 9 may include: a deformation loading control component, a droplet generation control component, an image acquisition control component, and a time synchronization control component. The deformation loading control component is electrically connected to the deformation loading mechanism 3 and is used to send loading control commands to the deformation loading mechanism 3, controlling the deformation loading mechanism 3 to start, stop, or switch loading modes according to preset loading parameters to apply a preset type of deformation to the flexible material 7 under test. The droplet generation control component is electrically connected to the droplet array generation mechanism 4 and is used to send dispensing control commands to the droplet array generation mechanism 4, controlling the droplet array generation mechanism 4 to generate test droplets 8 in the open test area 71 according to preset dispensing parameters. The image acquisition control component is electrically connected to the image acquisition mechanism 5 and is used to send acquisition control commands to the image acquisition mechanism 5, controlling the top-view image acquisition component 52 and the side-view image acquisition component 53 to perform image acquisition according to preset sampling frequency, acquisition time, or triggering conditions. The time synchronization control unit is electrically connected to the deformation loading control unit, droplet generation control unit, and image acquisition control unit, respectively. It sends a unified time reference signal to each of these control units, ensuring that the deformation loading, droplet generation, and image acquisition processes are within the same test timing sequence. Specifically, the time synchronization control unit sends a loading start time signal to the deformation loading control unit, a dispensing start time signal to the droplet generation control unit, and an acquisition trigger time signal to the image acquisition control unit, while keeping the time deviation between these times within a preset range. Through the unified timing scheduling of the time synchronization control unit, time misalignment between the deformation loading, droplet generation, and image acquisition processes can be avoided. This ensures that the image data acquired by the image acquisition mechanism 5 accurately reflects the actual behavior of the test droplet 8 under a specific deformation state, establishing a precise correspondence between deformation parameters, dispensing parameters, and droplet behavior states. This provides a time-consistent foundation for subsequent data correlation analysis by the data processing mechanism 6.

[0075] The testing process of this device is as follows: (1) Sample installation. The flexible material 7 to be tested is installed between the fixed clamp 21 and the movable clamp 22, so that the middle part of the flexible material 7 is within the open test area 71. The initial size of the flexible material 7 and the position of the open test area are recorded. The flexible material 7 to be tested is installed on the sample fixing module, so that the middle test area is within the open test window; the initial length, width, thickness and test area position of the material to be tested are obtained and recorded by means of vernier calipers, thickness gauges, displacement scales or image calibration. The initial length is used to calculate the compression ratio or elongation ratio, and the test area position and size are used to determine the droplet array arrangement range, image recognition range, continuous liquid path feature length and liquid residual area statistical range; (2) Droplet array arrangement. Multiple spaced test droplets 8 are formed in the open test area 71 by the droplet array generation mechanism 4. The number, volume, initial center distance, and array arrangement of the test droplets 8 are recorded. Multiple spaced test droplets are formed in the central test area by the droplet array generation module, and the number, volume, initial center distance, array arrangement, and droplet type of the test droplets are obtained. The number of droplets and the array arrangement are determined by the array dispensing template, multi-channel dispensing head, or automatic dispensing program. The droplet volume is set by the micro-syringe, pipette, or automatic dispensing unit. The initial center distance is obtained by the array template hole spacing, the dispensing program setting value, or the top view image calibration measurement. The above parameters are used to determine the droplet bridging judgment object, calculate the droplet center distance change rate, and statistically analyze the initial droplet coverage area, and serve as the initial benchmark for bridging risk assessment under different droplet types and different array conditions. (3) Deformation loading. Compression, tension, bending or cyclic deformation is applied to the flexible material 7 to be tested by the deformation loading mechanism 3. Taking compression deformation as an example, the movable clamp 22 moves toward the fixed clamp 21, so that the flexible material 7 to be tested is compressed along the length direction. The degree of compression can be expressed by the shortening ratio of the current length to the initial length and recorded as a percentage.

[0076] (4) Synchronous image acquisition. During the deformation loading process, the state changes of the test droplet 8 are synchronously acquired through the top view image acquisition unit 52 and the side view image acquisition unit 53. The top view image is used to identify the center position of the droplet, the center distance of the droplet, the liquid bridge area and the continuous liquid path 81; the side view image is used to observe the droplet outline, the degree of droplet spreading and the liquid residue area 82 after unloading and recovery.

[0077] (5) Bridging identification. The data processing unit 6 determines the droplet bridging status based on whether a continuous liquid neck is formed between adjacent test droplets 8. When a continuous liquid neck appears between two adjacent test droplets 8, and the liquid neck can remain stable within a set time, it is determined that droplet bridging has occurred between the two test droplets 8. When three or more test droplets 8 are connected sequentially through liquid bridges and form a continuous liquid channel of a certain length, it is determined that a continuous liquid path 81 has been formed.

[0078] The data processing module identifies droplet boundaries, droplet centers, liquid bridge regions, continuous liquid path regions, and liquid residue regions. Based on the image acquisition time, the droplet bridging determination results at each moment are matched with the synchronously recorded real-time deformation parameters to establish the correspondence between droplet bridging state and changes in compression ratio, elongation ratio, bending curvature, or number of cyclic loading cycles. This is used to determine the initial bridging conditions and continuous liquid path formation conditions. (6) Evaluation index calculation. The data processing unit 6 determines the critical bridging deformation parameter based on the deformation parameter and image recognition results. The critical bridging deformation parameter refers to the deformation parameter corresponding to the first formation of a liquid bridge between adjacent test droplets 8. When the deformation mode is compression, the critical bridging deformation parameter is the critical bridging compression ratio; when the deformation mode is tension, the critical bridging deformation parameter is the critical bridging tension ratio; when the deformation mode is bending, the critical bridging deformation parameter is the critical bridging bending state; when the deformation mode is cyclic loading, the critical bridging deformation parameter is the number of cyclic loading cycles corresponding to the first occurrence of droplet bridging.

[0079] The data processing unit 6 also obtains the droplet center distance change, continuous liquid path length, number of liquid bridges and liquid residue area based on the image recognition results, and further outputs evaluation results such as liquid path connectivity, liquid bridge breakage rate and liquid residue rate.

[0080] The dynamic water-repellent stability of the test material is evaluated based on the formation of droplet bridging and continuous liquid channels. If no droplet bridging occurs within the preset deformation range, or if droplet bridging occurs but no further continuous liquid channels are formed, and the droplets can redisperse with minimal liquid residue after unloading, the material is considered to have good dynamic water-repellent stability. If continuous liquid channels appear within the preset deformation range, or if significant liquid residue remains after unloading, the material is considered to have a risk of deformation-induced wetting and interconnection.

[0081] 8) Result Output. Based on the critical bridging deformation parameters, fluid path connectivity, fluid bridge breakage rate, and liquid residue rate, the test results of the flexible material 7 under test are output. The test results include the initial droplet bridging conditions, continuous fluid path formation conditions, fluid bridge breakage after unloading, and liquid residue status. If the flexible material 7 under test does not experience droplet bridging within the preset deformation range, or only experiences localized droplet bridging but does not form a continuous fluid path, and the fluid bridge breaks after unloading without forming a continuous residual channel, then its dynamic water-repellent stability is considered good. If a continuous fluid path is formed within the preset deformation range, or a fluid bridge or continuous residual channel still exists after unloading, then it is considered to have a risk of deformation-induced wetting and connectivity. In one embodiment, the test droplets 8 are arranged in a 3-row × 4-column rectangular array, with a total of 12 test droplets. The initial center distance between adjacent test droplets along the loading direction is 5 mm, and the initial center distance perpendicular to the loading direction is 5 mm. This array arrangement allows for simultaneous observation of the droplet center distance changes, droplet proximity, and droplet bridging states in both the loading direction and perpendicular to the loading direction.

[0082] Example 1 This embodiment uses the above-mentioned testing device to conduct compression deformation bridging tests on flexible superhydrophobic bulk materials under standard aqueous droplet conditions.

[0083] The dimensions of the flexible material 7 to be tested are 60 mm × 30 mm × 8 mm, and the dimensions of the open test area 71 are 40 mm × 20 mm. The flexible superhydrophobic bulk material to be tested is placed between the fixed clamp 21 and the movable clamp 22, and its two ends are clamped by flexible protective clips, so that its upper surface is within the open test area 71. Twelve standard aqueous phase droplets are arranged in the open test area 71 by the droplet array generation mechanism 4. The standard aqueous phase droplets can be deionized water droplets as the reference test droplets 8, with a single droplet volume of 10 μL. The droplet array is a 3-row × 4-column rectangular array, with an initial center distance of 5 mm between adjacent droplets along the loading direction and an initial center distance of 5 mm perpendicular to the loading direction.

[0084] like Figure 7 As shown, in the initial state, the test droplets 8 are dispersed, and no liquid bridges appear between them. As the deformation loading mechanism 3 drives the moving clamp 22 to move towards the fixed clamping end, the flexible superhydrophobic bulk material under test is compressed along its length. The test droplets 8 show a tendency to approach each other along the loading direction in the top view image. When the compression rate reaches 10% and 20%, the test droplets 8 remain dispersed, with only slight positional migration, and no liquid bridge area is identified. When the compression rate reaches +30%, a liquid bridge connection area appears for the first time between adjacent test droplets 8, that is, a continuous liquid connection is formed between two originally dispersed droplets, and it can remain stable within a set time. Therefore, it is determined that the first droplet bridging has occurred, and the critical bridging compression rate is 30%. Continuing to increase the compression rate, when the compression rate reaches 40%, the number of liquid bridges increases, and the local liquid path connectivity increases, but a continuous liquid path 81 covering the entire array direction has not yet been formed. When the compression rate reaches 50%, three or more test droplets 8 are connected sequentially through liquid bridges to form a continuous liquid path 81. Among them, Figure 7 In the diagram, F represents the compressive force applied to both sides of the flexible material 7 under test, with opposite directions and forces in pairs; the blue double arrows indicate the droplet migration direction; H0 is the initial uncompressed thickness of the flexible material 7 under test, and H1, H2, and H3 are the thicknesses of the flexible material 7 under test after compression at the corresponding compression ratios, with H0 < H1 < H2 < H3; L0 is the initial uncompressed length of the flexible material 7 under test, and L1, L2, and L3 are the lengths of the flexible material 7 under test after compression at the corresponding compression ratios, with L0 > L1 > L2 > L3; d x0 d x1 d x2 d x3 The center-to-center distance of adjacent droplets along the x-direction is shown in four states: uncompressed initial state, low compressibility, medium compressibility, and high compressibility; all four states are almost equal. y0 d y1 d y2 d y3The distance between adjacent droplet centers along the y-direction represents four states: uncompressed initial state, low compressibility, medium compressibility, and high compressibility, with each state gradually decreasing. ε is the compressibility, ε1 is the critical compressibility at which droplets begin to approach each other significantly, and ε2 is the critical compressibility at which droplets begin to bridge, with ε1 < ε2.

[0085] like Figure 8 As shown, the degree of fluid connectivity gradually increases with the compression ratio from 0% to 50%. When the compression ratio is below 30%, the fluid connectivity is close to zero; after the compression ratio reaches 30%, the fluid connectivity begins to increase significantly; and at 50% compression ratio, continuous fluid channels 8116 are formed, indicating that this flexible superhydrophobic bulk material faces the risk of deformation-induced droplet bridging and localized wetting connectivity under large compressive deformation. Specifically, in... Figure 8 In this context, ε is the compressibility, ε1 is the critical compressibility at which the droplets begin to approach each other significantly, and ε2 is the critical compressibility at which the droplets begin to bridge, with ε1 < ε2.

[0086] like Figure 9 As shown, after unloading and recovery, the tested flexible superhydrophobic bulk material rebounded, some liquid bridges broke, and some test droplets 8 redispersed. However, a small amount of liquid residue 82 could still be observed in local areas. The data processing mechanism 6 can further obtain the liquid bridge breakage rate and liquid residue rate after unloading and recovery, which can be used to evaluate the material's ability to recover its dispersed water-repellent state after deformation. Among these, in... Figure 9 In the diagram, F represents the compressive force applied to both sides of the flexible material 7 under test; H0 represents the initial uncompressed thickness of the flexible material 7 under test, and H1, H2, and H3 represent the thicknesses of the flexible material 7 under test after compression at the corresponding compression ratios, with H0 < H1 < H2 < H3; L0 represents the initial uncompressed length of the flexible material 7 under test, and L1, L2, and L3 represent the lengths of the flexible material 7 under test after compression at the corresponding compression ratios, with L0 > L1 > L2 > L3; d y0 d represents the center distance along the y-direction during the droplet loading stage. y1 Let d be the center distance along the y-direction during droplet recovery. y2 To further recover the center distance along the y-direction in the droplet, d y3 This allows the droplets to essentially restore their center-to-center distance along the y-direction.

[0087] This embodiment demonstrates that although the tested flexible superhydrophobic bulk material can maintain a good superhydrophobic state under static conditions, droplet migration, approach, bridging, and the formation of continuous liquid channels 81 may still occur under compression deformation. This result shows that the present invention can identify deformation-induced wetting connectivity risks that are difficult to detect with traditional static single-droplet contact angle tests.

[0088] Example 2 This embodiment uses the aforementioned testing apparatus to conduct compression deformation bridging tests on flexible superhydrophobic bulk materials under artificial contaminated droplet conditions. The dimensions and fixing method of the flexible superhydrophobic bulk material under test are the same as in Embodiment 1.

[0089] The artificial dirt droplets consist of an aqueous base solution, soluble salts, solid dirt particles, and a colorimetric reagent. The aqueous base solution is deionized water; the soluble salt is sodium chloride (1% by mass); the solid dirt particles are kaolin (0.2% by mass); and the colorimetric reagent is methylene blue (0.005% by mass). The resulting artificial dirt droplets are used to simulate a complex aqueous droplet environment containing salt, particles, and a certain degree of conductivity.

[0090] Twelve artificial contaminant droplets are arranged in the open test area 71 by the droplet array generation mechanism 4. The volume of each droplet is 10 μL. The droplet array is a rectangular array of 3 rows × 4 columns. The initial center distance between adjacent droplets along the loading direction is 5 mm, and the initial center distance perpendicular to the loading direction is 5 mm.

[0091] During the test, the deformation loading mechanism 3 applied compression deformation step by step in the same loading method as in Example 1. When the compression ratio was less than 30%, no stable liquid bridge was formed between the artificial dirt droplets; when the compression ratio reached 30%, a continuous liquid neck appeared between adjacent artificial dirt droplets, indicating that the first droplet bridging had occurred; when the compression ratio reached 40%, a continuous liquid path 81 was formed between multiple droplets, indicating that the material was more likely to have liquid communication under artificial dirt droplet conditions.

[0092] Compared to Example 1, the compression ratio required to form the continuous liquid path 81 in Example 2 was reduced from 50% to 40%. This result indicates that under conditions containing salt and particulate contaminants, the spread, adhesion, and residue tendency of the test droplets 812 are enhanced, and the ability of the tested flexible superhydrophobic bulk material to maintain a multi-droplet dispersed water-repellent state under deformation conditions is reduced.

[0093] After unloading and recovery, observations using the side view image acquisition unit 53 and the top view image acquisition unit 52 revealed that a relatively obvious liquid residue area 82 still existed under the artificial contamination droplet conditions. The liquid residue rate calculated by the data processing unit 610 was higher than that in Example 1, indicating that complex aqueous droplets are more likely to cause local wetting residue after deformation recovery.

[0094] This embodiment demonstrates that the present invention is not only applicable to deformation-induced droplet bridging tests under standard aqueous droplet conditions, but also to bridging risk assessment under complex aqueous droplet conditions such as artificially contaminated droplets, salt solution droplets, and acidic simulated rainwater droplets, thereby improving the applicability of the testing device and method to actual service environments.

[0095] Comparative Example 1 Comparative Example 1 uses a conventional static single-droplet contact angle test method to test the same flexible superhydrophobic bulk material. During the test, a single 5 μL aqueous phase droplet is added to the material surface, and the static water contact angle and roll-off angle are obtained using a contact angle measuring instrument.

[0096] Test results show that the material has a high water contact angle and a low roll-off angle under static conditions, indicating that it has good static superhydrophobic properties. However, since this test method only observes the wetting state of a single droplet on the surface of an undeformed material, it cannot reflect whether multiple droplets migrate, approach, bridge, or form a continuous liquid path 81 during compression, stretching, bending, or cyclic deformation.

[0097] like Figure 10 As shown, Comparative Example 1 demonstrates that the material surface possesses static water-repellent characteristics, but it cannot identify the risk of deformation-induced droplet bridging. Therefore, relying solely on static single-droplet contact angle testing is insufficient to comprehensively evaluate the dynamic water-repellent stability of flexible superhydrophobic bulk materials under actual stress conditions.

[0098] Comparative Example 2 Comparative Example 2 uses the same droplet array arrangement as Example 1. Twelve test droplets 8 are arranged on the surface of the flexible superhydrophobic bulk material to be tested. The volume of a single droplet is 10 μL. The initial center distance between adjacent test droplets 8 along the loading direction is 5 mm, and the initial center distance perpendicular to the loading direction is 5 mm. However, no deformation loading is applied to the flexible superhydrophobic bulk material to be tested.

[0099] Under non-deformation conditions, the droplet array was continuously observed for 300 s. The results showed that the test droplet 8 remained basically dispersed within 300 s, and no stable liquid bridge region was observed, nor was a continuous liquid path 81 formed. This result indicates that the droplet bridging in Examples 1 and 2 was not simply caused by the static process, but was related to the changes in droplet center distance, surface structure, and local wetting state of the flexible superhydrophobic bulk material under deformation.

[0100] like Figure 10 As shown, Comparative Example 2 did not form droplet bridging under non-deformation conditions, while both Example 1 and Example 2 showed droplet bridging under compression deformation, indicating that the present invention can effectively identify deformation-induced multi-droplet wetting and connectivity behavior.

[0101] Testing and Evaluation like Figure 10As shown, there are significant differences in the test results of Example 1, Example 2, Comparative Example 1, and Comparative Example 2. Comparative Example 1 uses a static single droplet contact angle test, which can obtain a high water contact angle and a low roll-off angle, but it cannot determine whether multiple droplets bridge under deformation conditions. Comparative Example 2 arranges multiple droplets under non-deformation conditions, and the droplet array does not form liquid bridges within 300 s, indicating that droplet bridging is not simply caused by the static process.

[0102] In Example 1, a compression deformation test was conducted under standard aqueous droplet conditions. The first droplet bridging occurred when the compression ratio reached 30%, and a continuous liquid path 81 was formed when the compression ratio reached 50%. In Example 2, when artificial contaminated droplets were used for testing, the first droplet bridging occurred when the compression ratio reached 30%, and a continuous liquid path 81 was formed when the compression ratio reached 40%. After unloading and recovery, there was a significant liquid residue area 82.

[0103] Therefore, the testing device and method provided by this invention can simultaneously obtain deformation parameters, droplet array changes, liquid bridge formation state, and liquid residue state under the same testing sequence, and can identify deformation-induced wetting connectivity risks that are difficult to detect by traditional static wetting tests. Especially for flexible superhydrophobic bulk materials, this invention can evaluate their ability to maintain a dispersed water-repellent state under multi-droplet and complex aqueous droplet conditions, thereby providing a basis for material formulation screening, structural optimization, dynamic water-repellent stability evaluation, and risk assessment before engineering applications.

[0104] The above-mentioned Examples 1, 2, Comparative Example 1 and Comparative Example 2 were tested and evaluated, and the test results are shown in Table 1.

[0105] Table 1 Test Results

[0106] As shown in Table 1, both Examples 1 and 2 exhibited high water contact angles and low roll-off angles in their initial states, indicating that the tested materials possessed excellent static superhydrophobic properties. However, under compressive deformation, both examples showed droplet bridging behavior. Specifically, Example 1 showed initial droplet bridging at a compression ratio of 30%, and formed a continuous liquid path 81 at a compression ratio of 50%. Example 2, tested with artificially contaminated droplets, also showed initial droplet bridging at a compression ratio of 30%, but formed a continuous liquid path 81 at a compression ratio of 40%, and exhibited significant liquid residue after unloading. This indicates that complex aqueous droplets increase the risk of deformation-induced wetting and connectivity in flexible superhydrophobic bulk materials. Comparative Example 1 is a single droplet test without deformation. Although it can obtain the static water contact angle and roll-off angle, it cannot evaluate the bridging behavior of multiple droplets under deformation conditions. Comparative Example 2 did not form a liquid bridge within 300 s under the condition of static placement of multiple droplets without deformation, indicating that the droplet bridging in the examples is mainly induced by material deformation, rather than simply caused by the droplet placement process.

[0107] In summary, the flexible material deformation-induced droplet bridging testing device provided in this embodiment exposes the middle part of the flexible material 7 under test to form an open testing area 71 through the sample fixing mechanism 2, providing a clear testing window for droplet generation and image acquisition; the deformation loading mechanism 3 applies compression, tension, bending or cyclic deformation to the flexible material 7 under test within the open testing area 71, realizing the deformation loading of the material under controlled conditions; the droplet array generation mechanism 4 generates multiple spaced test droplets 8 in a preset array form within the open testing area 71, providing a controllable test object for observing multi-droplet bridging behavior; the image acquisition mechanism 5 collects the droplet behavior characteristics of the test droplets 8 during the deformation loading and unloading process, realizing the visual recording of droplet behavior; and the data processing mechanism 6 performs correlation analysis based on image data and deformation loading data, realizing the establishment of the correspondence between deformation parameters and droplet behavior. The aforementioned mechanisms work in concert to integrate deformation loading, droplet array generation, image acquisition, and data processing into a single system. This allows for the simultaneous acquisition of deformation parameters, droplet array changes, and droplet bridging states of the flexible material under test 7 within the same testing sequence. This effectively solves the problem in existing technologies where the lack of an integrated structure matching the deformation loading process for sample fixation, deformation loading, droplet array generation, and image acquisition makes it difficult to simultaneously acquire deformation parameters and droplet behavior states within the same testing sequence, thus hindering in-situ observation and evaluation of multi-droplet bridging behavior under deformation conditions. This technical solution does not simply perform static contact angle testing on materials; rather, it addresses the potential issues of multi-droplet migration, proximity, bridging, formation of continuous liquid channels 81, and liquid residue after unloading that may occur in flexible superhydrophobic bulk materials during compression, tension, bending, or cyclic deformation. It constructs a testing scheme integrating deformation loading, droplet array generation, synchronous image acquisition, bridging recognition, data processing, and result evaluation.

[0108] Furthermore, by setting up an open test area 71, the device ensures that the central droplet test area is not obstructed by the fixture while the flexible material 7 under test is being clamped and loaded. This enables in-situ synchronous acquisition of droplet array arrangement, top view image acquisition, and side view image acquisition, improving the observability and repeatability of deformation wetting test. By using multiple spaced test droplets 8 as test objects, the device can observe the transformation process of droplets from a dispersed state to migration, approach, bridging, continuous liquid path 81, and unloading residual state, thereby identifying deformation-induced wetting connection risks that are difficult to detect by traditional contact angle and roll-off angle tests.

[0109] Furthermore, this device can calculate evaluation indicators such as critical bridging deformation parameters, droplet center distance change rate, liquid path connectivity, liquid bridge breakage rate, and liquid residue rate, transforming droplet bridging behavior from qualitative observation to calculable, comparable, and repeatable quantitative evaluation results. Simultaneously, the test droplets 8 include not only standard aqueous phase droplets such as deionized water, but also environmental simulation droplets such as salt solution droplets, artificially contaminated droplets, dyed droplets, acidic simulated rainwater droplets, and alkaline simulated droplets. This can simulate the actual service environment of flexible materials under rainwater, salt spray, condensation, contamination deposition, and complex aqueous phase pollution conditions, improving the engineering applicability of the testing method. This invention is applicable to the dynamic water-repellent stability evaluation of flexible superhydrophobic bulk materials, flexible insulating and protective materials, anti-fouling flashover water-repellent materials, anti-condensation materials, and porous elastic hydrophobic bulk materials, providing testing basis for material formulation screening, structural optimization, durability evaluation, and risk assessment before engineering applications.

[0110] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0111] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0112] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A flexible material deformation-induced droplet bridging testing device, characterized in that, include: The base support mechanism is used to provide a supporting foundation to provide support. A sample fixing mechanism is provided on the base support mechanism to fix the end or edge area of ​​the flexible material to be tested, and to expose the middle part of the flexible material to be tested to form an open test area. A deformation loading mechanism is disposed on the base support mechanism and connected to the sample fixing mechanism, and is used to apply compression, tension, bending or cyclic deformation to the flexible material to be tested; A droplet array generation mechanism is disposed above the sample fixing mechanism and is used to form multiple test droplets distributed at intervals on the surface of the flexible material to be tested in a preset array in the open test area. An image acquisition mechanism, mounted on the base support mechanism, is used to acquire the droplet behavior characteristics of the test droplet during deformation loading and unloading processes; The data processing mechanism is electrically connected to the image acquisition mechanism and the deformation loading mechanism, respectively, and is used to analyze the behavior of the test droplet during deformation and unloading based on the image data acquired by the image acquisition mechanism and the deformation loading data of the deformation loading mechanism, so as to evaluate its ability to maintain the multi-droplet dispersion state under deformation conditions.

2. The flexible material deformation-induced droplet bridging testing device according to claim 1, characterized in that, The sample fixing mechanism includes: A fixing clamp is used to clamp one end of the flexible material to be tested; A movable clamping member is disposed on one side of the fixed clamping member in a manner opposite to the fixed clamping member, and the movable clamping member can move toward or away from the fixed clamping member to clamp the other end of the flexible material to be tested and cause the flexible material to be tested to undergo compression or stretching deformation.

3. The flexible material deformation-induced droplet bridging testing device according to claim 2, characterized in that, The clamping ends of the fixed clamping member and / or the movable clamping member are provided with flexible protective clips for clamping and protecting the flexible material to be tested.

4. The flexible material deformation-induced droplet bridging testing device according to claim 2, characterized in that, The deformation loading mechanism includes: A movable drive unit, the power output end of which is connected to the movable clamping unit, is used to drive the movable clamping unit to move toward or away from the fixed clamping unit in order to apply tension, bending or cyclic deformation to the flexible material to be tested. A bending support is disposed below the sample fixing mechanism and has an arc-shaped support surface. It is used to contact and cooperate with the lower surface of the flexible material under test during bending test, so that the flexible material under test bends under the drive of the moving clamp and forms a preset bending radius or bending curvature.

5. The flexible material deformation-induced droplet bridging testing device according to any one of claims 1 to 4, characterized in that, The droplet array generation mechanism is any one of a micro-syringe, a multi-channel liquid dispensing head, an array liquid distribution template, or an automatic liquid dispensing unit. By controlling the liquid dispensing position, liquid dispensing volume, and liquid dispensing quantity, test droplet arrays with different array forms and / or different droplet parameters can be formed on the test surface. The preset array form can be any one of a linear array, a rectangular array, a circular array, or a gradient spacing array.

6. The flexible material deformation-induced droplet bridging testing device according to any one of claims 1 to 4, characterized in that, The image acquisition includes: A light source is used to emit light to enhance the image contrast of droplet boundaries, liquid bridge necks, and liquid residue areas; The top-view image acquisition device is used to acquire the changes in the planar position of the test droplet, the changes in the center distance of the droplet, the formation of liquid bridges, and the formation of continuous liquid paths during the deformation process; The side view image acquisition device is used to acquire the contour morphology, spreading state, contact state, and residual state of the liquid after unloading and recovery of the test droplet; A calibration ruler is used to spatially calibrate the pixel dimensions of an image. The trigger acquisition unit is used to trigger the top view image acquisition unit and the side view image acquisition unit to acquire images when the flexible material under test reaches a preset deformation, preset loading time, or preset number of loading cycles.

7. The flexible material deformation-induced droplet bridging testing device according to any one of claims 1 to 4, characterized in that, Also includes: A synchronous control mechanism is electrically connected to the droplet array generation mechanism, the deformation loading mechanism, and the image acquisition mechanism, respectively, and is used to control the deformation loading parameters, droplet arrangement parameters, and image acquisition time to be within the same test sequence.

8. The flexible material deformation-induced droplet bridging test device according to any one of claims 1 to 4, characterized in that, The image recognition data acquired by the image acquisition mechanism and the deformation loading data of the deformation loading mechanism are analyzed and calculated to evaluate its ability to maintain a multi-droplet dispersed water-repellent state under deformation conditions. Specifically, if no droplet bridging occurs within the preset deformation range or no continuous liquid path is formed after droplet bridging, and the droplets are redispersed after unloading and the residual liquid coverage area is less than the preset threshold, then the dynamic water-repellent stability of the flexible material under test is deemed qualified. If droplet bridging occurs within a preset deformation range and forms a continuous liquid path connecting adjacent droplets, or if the residual liquid coverage area after unloading is greater than or equal to a preset threshold, then the material is determined to have a risk of deformation-induced wetting and connection.

9. The flexible material deformation-induced droplet bridging testing device according to any one of claims 1 to 4, characterized in that, The analysis and calculation based on the image recognition data acquired by the image acquisition mechanism and the deformation loading data of the deformation loading mechanism are used to evaluate its ability to maintain a multi-droplet dispersed water-repellent state under deformation conditions. Specifically, the analysis and calculation are performed based on the image recognition data acquired by the image acquisition mechanism and the deformation loading data of the deformation loading mechanism to confirm the dynamic water-repellent parameters of the flexible material under test, so as to evaluate its ability to maintain a multi-droplet dispersed water-repellent state under deformation conditions.

10. The flexible material deformation-induced droplet bridging testing device according to claim 9, characterized in that, The dynamic water-repellent parameters of the flexible material under test include: critical bridging deformation parameters, liquid path connectivity, liquid bridge breakage rate after unloading and recovery, and liquid residue rate; wherein, the critical bridging deformation parameters are the compression ratio, tensile ratio, bending curvature, or number of cyclic loading cycles corresponding to the first occurrence of droplet bridging.

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