A method for wettability transition and superhydrophobicity quantitative modulation based on numerical calculation

Abstract

A method for quantitative modulation of wettability transition and superhydrophobicity based on numerical calculation, which first selects a preparation process procedure and determines dependent and independent variables according to engineering requirements; secondly, the original data points of the wettability transition under the selected preparation process procedure are collected and a basic database of wettability transition is formed, and at the same time, the original fitting of the natural influence law is performed based on the determined wettability transition dependent and independent variables; thirdly, a wettability transition fitting prediction method based on the numerical calculation principle is selected; finally, quantitative and precise modulation of wettability transition and superhydrophobicity is performed based on a numerical calculation fitting prediction method with higher fitting accuracy to meet engineering applications with specific functional requirements; the present invention will have profound value and significance for applying superhydrophobic surfaces to actual engineering needs, especially in fields with high precision requirements such as high-speed and long-distance continuous transport of droplets and droplet operations based on different adhesions.

Description

Technical Field

[0001] The present invention relates to the technical field of wettability transformation and quantitative and precise control preparation for obtaining super-hydrophobic extreme wettability, and in particular to a wettability transformation and super-hydrophobic quantitative modulation method based on numerical calculation. Background Art

[0002] Extremely wettable functional surfaces based on biomimetic manufacturing have broad application prospects in aerospace, national defense, military, petrochemical, electronic information, biomedicine, and energy consumption due to their unique properties such as self-cleaning, anti-icing, sliding drag reduction, corrosion resistance, microfluidic chips, and droplet transport. Accordingly, many functional applications related to them require quantitative and precise control of wettability transformations. For example, droplet transport based on the wettability gradient effect, that is, if the wettability gradient can be continuously and precisely controlled, performance improvements can be achieved in terms of transport rate and droplet recovery efficiency; or quantitative and precise control based on different adhesion properties can be applied to precise droplet manipulation robots to solve drug dispensing quality issues in the medical field.

[0003] At the same time, the typical traditional super-hydrophobic surface preparation methods mainly include dip coating, grafting, electrospinning, etching, template method, etc., which are unable to achieve quantitative and accurate acquisition of wettability transition and super-hydrophobic extreme wettability. Specifically, for intrinsic hydrophobicity, the surface is generally texturized to amplify the roughness to obtain wettability transition or super-hydrophobic properties, but this process is generally robust, and only the change in static contact angle before and after treatment is compared; at the same time, for intrinsic hydrophilic materials, on the basis of obtaining surface texturing to increase the roughness, low surface energy modification methods such as dip coating are combined to achieve wettability transition and super-hydrophobic surface preparation. This process is still only based on the steady-state robustness evaluation of wettability under the control principle, and the influence law of wettability transition under its apparent parameters can only be limited to the selection and modulation of existing data. This has led to the current wettability transition and the acquisition of super-hydrophobic extreme wettability being based on robust regulation under the control premise and having modulation limitations. Therefore, whether it is possible to achieve quantitative and accurate modulation and prediction of the wettability transformation of the material substrate surface and the extreme wettability of superhydrophobicity is a huge obstacle to the application of superhydrophobic and other wettability functional surfaces to actual engineering needs, especially in areas with high requirements for wettability accuracy. Summary of the Invention

[0004] In order to overcome the defects of the above-mentioned prior art, the purpose of the present invention is to provide a wettability transition and super-hydrophobic quantitative modulation method based on numerical calculation, which can be effectively integrated with the current process methods for wettability transition and super-hydrophobic surface acquisition to meet the engineering needs of quantitative precise modulation and predictive preparation. It will have profound value and significance for applying super-hydrophobic surfaces to actual engineering needs, especially in fields with high precision requirements such as high-speed and long-distance continuous transport of droplets and droplet operations based on different adhesion properties.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A method for quantitative modulation of wettability transition and superhydrophobicity based on numerical calculation, which first selects the preparation process procedures and determines the dependent and independent variables according to engineering requirements; secondly, the original data points of wettability transition under the selected preparation process procedures are collected to form a basic database of wettability transition, and at the same time, the original fitting of natural influence laws is performed based on the determined wettability transition dependent and independent variables; thirdly, the wettability transition fitting prediction method based on the numerical calculation principle is selected; finally, the wettability transition and superhydrophobicity are quantitatively and accurately modulated and predicted based on the numerical calculation fitting prediction method with higher fitting accuracy to meet engineering applications with specific functional requirements.

[0007] A method for wettability transformation and superhydrophobicity quantitative modulation based on numerical calculation comprises the following steps:

[0008] 1) Determine the required wettability control and the preparation process for obtaining superhydrophobic extreme wettability according to engineering requirements;

[0009] 2) Determine the dependent and independent variables that affect wettability transition and superhydrophobicity realization based on the preparation process specifications, that is, determine the independent and dependent variables under quantitative and precise modulation and fitting prediction; the dependent variables are static contact angle or rolling angle, etc.; the independent variables are aging treatment time under temperature-controlled aging strategy, concentration of low surface energy modification reagents or modification time under various dip-coating methods, etc.;

[0010] 3) collecting raw data points of the invasiveness transition based on the dependent variable and independent variable established in step 2) and forming a corresponding invasiveness transition basic database;

[0011] 4) Based on the establishment of a basic database of wettability transition, perform original fitting of the natural laws of wettability transition;

[0012] 5) Based on step 4), the wettability transition is selected based on the fitting prediction method under numerical calculation, namely:

[0013] 5.1) Using Matlab programming to implement fitting prediction curves based on the cubic spline numerical calculation principle and the least squares numerical calculation method;

[0014] 5.2) Determine whether the predicted fit is distorted based on whether the boundary conditions for wettability transition, i.e., contact angles and rolling angles that are not negative or exceed 180°, are less than the critical limit under functional requirements, and natural transition laws such as accidental mutation points, are met, and make corresponding adjustments. That is, if distortion occurs in the fitting prediction based on the cubic spline numerical calculation principle, remove the accidental error points based on the slope gradient, and then re-fit and predict the wettability transition law based on the cubic spline numerical calculation principle until no distortion occurs. Similarly, if distortion occurs in the fitting prediction based on the least squares numerical calculation principle, remove the accidental error points and change the highest-order parameter of the polynomial fitting simultaneously, so that the error generated by the fitting prediction based on the least squares numerical calculation is as small as possible, until no distortion occurs.

[0015] 6) When the two methods based on the above numerical calculation principle are fitted to the optimal state, a comparison based on the wettability fitting accuracy is performed to determine the final numerical calculation fitting prediction method; at the same time, quantitative and precise modulation and experimental verification of the wettability transition and superhydrophobicity achieved under this numerical calculation fitting prediction method are carried out to meet engineering applications with specific functional requirements, such as high-speed and long-distance continuous droplet transportation and droplet manipulation based on different adhesion gradients.

[0016] The preparation process of step 1) includes wettability regulation and super-hydrophobicity realization process under temperature control aging strategy, wettability regulation and super-hydrophobicity realization process based on dip coating method, and wettability regulation and super-hydrophobicity realization process based on template method.

[0017] The wettability transformation basic database in step 3) includes a two-dimensional mathematical model database and a multi-dimensional wettability transformation original database formed based on the response surface method.

[0018] The fitting prediction method of wettability transition based on numerical calculation includes logical algorithms based on the cubic spline numerical calculation principle and logical algorithms based on the least squares numerical calculation principle implemented by any programming language or software, and also includes numerical calculation principles and methods for similar data fitting prediction implemented with the least squares method or cubic spline.

[0019] Solutions to the distortion phenomenon in step 5.2) include elimination of accidental error points based on the slope gradient and repetitive cyclic fitting of prediction curves, as well as deeper distortion control and adaptive methods based on machine learning.

[0020] The engineering and technical applications of the wettability transition based on numerical calculation fitting prediction and the quantitative modulation method of superhydrophobicity include droplet transport based on wettability gradient and droplet operation based on different adhesion properties, as well as other engineering and technical applications that include quantitative and precise modulation and prediction characteristics of wettability.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] First, the present invention innovatively introduces the principle of numerical calculation into the quantitative and precise modulation of wettability transition and superhydrophobicity based on the preparation process regulations, overcoming the current defects of only being able to perform robust static contact angle transition comparison and being limited to the modulation and research of wettability transition and superhydrophobicity under known data; secondly, the wettability transition and superhydrophobicity extreme wettability modulation method based on the numerical calculation principle of the present invention can achieve quantitative, accurate to the ten thousandth place control preparation and result prediction under the allowed working conditions, and the error can be controlled below 3.2%, and the best effect can reach below 0.16%; in addition, the modulation technology method based on the present invention can be used to realize the actual engineering application of bionic extreme wettability surface, such as improving the droplet transport efficiency and transport volume control under wettability gradient, and droplet operation based on adhesion gradient to meet medical needs and other related technical applications.

[0023] The present invention can combine various types of currently existing wettability transition control and super-hydrophobic surface preparation process methods to achieve quantitative and accurate modulation and prediction, has good applicability, is not limited by experimental methods, has good repeatability and operability, and can significantly reduce manufacturing costs, providing an effective way for the application of high-precision wettability in actual engineering technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a flowchart of the present invention.

[0025] Figure 2 This is a natural law fitting curve of the original data of wettability transformation of various structured functional surfaces under the temperature control and aging control strategy in Example 1 of the present invention.

[0026] Figure 3 This is the wettability transformation law curve of various structured functional surfaces based on the temperature control and aging control strategy according to Example 1 of the present invention after fitting with cubic spline numerical calculation.

[0027] Figure 4 These are the wettability transformation law curves and fitting error values ​​of various structured functional surfaces based on the temperature control and aging control strategy according to Example 1 of the present invention, when the polynomial with the highest order term being 2 is fitted using the least squares numerical calculation.

[0028] Figure 5These are the wettability transformation law curves and fitting error values ​​of various structured functional surfaces based on the temperature control and aging control strategy according to Example 1 of the present invention, when the polynomial with the highest order term being 8 is fitted using the least squares numerical calculation.

[0029] Figure 6 The natural law curve of the wettability transformation and super-hydrophobicity modulation of the conical micro-nano composite structured surface that did not achieve super-hydrophobicity after 100°C-24h-temperature control and aging, as determined by cubic spline fitting in Example 1 of the present invention after comparing the fitting accuracy, as well as the fitting and prediction curve diagram and the experimental result diagram based on the prediction results; wherein a) is the natural law curve of the wettability transformation and super-hydrophobicity modulation of the conical micro-nano composite structured surface that did not achieve super-hydrophobicity after temperature control and aging, and b) is the fitting prediction curve diagram of whether the super-hydrophobic state can be achieved under the modulation prediction based on the method of the present invention and the experimental result diagram based on the predicted aging time.

[0030] Figure 7 This is a natural law curve of the original wettability transformation of the pyramidal micro-nano composite structured surface obtained by Example 2 of the present invention when the super-hydrophobic surface is not achieved through the temperature control and aging control strategy, as well as a fitting prediction curve diagram of whether the super-hydrophobic state can be achieved and whether the super-hydrophobic extreme wetting state of above 169° can be achieved under the modulation prediction based on the technical method of the present invention, and also includes an experimental result diagram based on the fitting prediction aging time; wherein Figure a) is a natural law curve of the original wettability transformation of the pyramidal micro-nano composite structured surface obtained by the temperature control and aging control strategy when the super-hydrophobic surface is not achieved, and b) is a fitting prediction curve diagram of whether the super-hydrophobic state can be achieved and whether the super-hydrophobic extreme wetting state of above 169° can be achieved under the modulation prediction based on the method of the present invention, and an experimental result diagram based on the predicted aging time. DETAILED DESCRIPTION

[0031] The present invention will be described in detail below with reference to the embodiments and accompanying drawings.

[0032] Example 1, as Figure 1 As shown, a method for wettability transformation and superhydrophobicity quantitative modulation based on numerical calculation includes the following steps:

[0033] 1) First, femtosecond laser micro-nanotexturing fabrication technology was used to prepare conical micro-nano composite structured surfaces, pyramidal micro-nano composite structured surfaces, cone-ridge micro-nano composite structured surfaces, adhesion micro-nano composite structured surfaces, and interconnected topological micro-nano composite structured surfaces with similar dimensional features, paving the way for raw data point acquisition based on the wettability transition and superhydrophobic extreme wetting properties under temperature-controlled aging.

[0034] 2) Selecting dependent and independent variables for the wettability transformation and superhydrophobicity of the complex multi-level micro-nano composite structured surface based on the temperature-controlled aging strategy. In this embodiment, the static contact angle is the dependent variable, and the temperature-controlled aging treatment time is the independent variable. At the same time, the temperature variables are set to 100°C and 150°C, and the aging time is 24 hours (the gradient of the wettability data point collection is 3 hours) to meet the establishment of a basic database of wettability transformation under different variables, reduce or avoid accidental errors, and provide sufficient original data points for the modulation method.

[0035] 3) Collecting raw data points of wettability transformation under the process specifications of 100°C and 150°C and aging treatment time of 24h, and forming a corresponding wettability transformation basic database;

[0036] 4) Based on the establishment of the wettability transition basic database, the original natural law fitting of the wettability transition is performed to obtain the original natural law curve of the wettability transition;

[0037] 5) Based on step 4), the wettability transition is selected based on the fitting prediction method under numerical calculation, namely:

[0038] 5.1) First, the natural law in step 4) is analyzed. That is, based on the original natural law in step 4), the five micro-nano composite structured surfaces under 150℃-24h temperature controlled aging treatment all achieve the extreme superhydrophobic properties. Figure 2 As shown in the figure, only part of the hydrophobic properties were achieved under the 100℃-24h temperature-controlled aging treatment, and the original data points of super-hydrophobic properties were not collected for comparative analysis. Therefore, the wettability transformation database at 150℃ was used to analyze and determine whether the fitting method under the numerical calculation principle has distortion and accuracy, as shown in the figure. Figures 3-5 As shown;

[0039] 5.2) Comprehensive comparative analysis Figure 3 That is, the wettability transition fitting curve after 150℃-24h based on the cubic spline numerical calculation, Figure 4 That is, the wettability transformation curve of various structured functional surfaces under the temperature control and aging control strategy is fitted by the least square numerical calculation when the highest order of the polynomial is 2, and Figure 5 That is, based on the wettability transition curves of various structured functional surfaces under the temperature control and aging control strategy, the least squares numerical calculation fitting of the polynomial with the highest order of 8 is used to select the fitting prediction method under the numerical calculation of wettability transition and apply it to the quantitative and precise modulation fitting and prediction of the wettability transition and superhydrophobicity of the conical micro-nano composite structured surface that has not achieved superhydrophobicity at 100℃-24h:

[0040] The results show that the fitting prediction based on the least squares numerical calculation principle has serious distortion, while the fitting prediction based on the cubic spline numerical calculation principle has higher accuracy and no distortion. Therefore, the fitting prediction method based on the cubic spline numerical calculation principle is selected as the fitting prediction method for quantitative modulation of wettability transition and superhydrophobicity under the temperature-controlled aging treatment process.

[0041] The natural law curve of the original wettability transformation of the conical micro-nano composite structured surface that did not achieve super-hydrophobic extreme wettability after 100℃-24h and the wettability transformation fitting prediction curve under the selected fitting prediction method based on the cubic spline numerical calculation principle were obtained, such as Figure 6 As shown;

[0042] 6) According to the fitting prediction aging time (58.17h) in step 5), a temperature-controlled aging treatment process is performed to verify the wettability transition law of the conical micro-nano composite structured surface that has not achieved super-hydrophobicity and the static contact angle experimental results, and to determine whether it can achieve super-hydrophobicity as predicted (output results such as Figure 6 The static contact angle of the conical micro-nano composite structured super-hydrophobic surface obtained under the fitting predicted aging treatment time is shown in Fig. Figure 6 As shown in (b), the super-hydrophobic state can be achieved at 154.818°, which verifies the correctness of the quantitative modulation method. Compared with the theoretically predicted value of 150.06502°, the fitting prediction error is 3.07%.

[0043] This embodiment can achieve quantitative and precise modulation and prediction of the wettability transformation and super-hydrophobicity of structured surfaces under the comprehensive control of femtosecond laser texturing and temperature control aging, and has universal applicability. It can achieve quantitative and precise modulation and prediction of wettability transformation and super-hydrophobicity based on the comprehensive control process regulations of different temperatures and aging times; at the same time, it plays an important role in promoting the practical engineering technology applications of wettability functional surfaces based on this process regulation, such as droplet transport under the wettability gradient effect and droplet manipulation with different adhesion. In addition, this embodiment can combine various types of wettability transformation control and super-hydrophobic surface preparation process methods currently available to achieve quantitative and precise modulation and prediction, has good applicability, is not limited by experimental methods, has good repeatability and operability, and can significantly reduce manufacturing costs, providing an effective way for the practical engineering technology applications of high-precision wettability.

[0044] Example 2: The original data points of wettability transformation of the conical micro-nano composite structured surface that does not achieve super-hydrophobicity under the 100°C temperature-controlled aging strategy in steps 5.2) and 6) of Example 1 are replaced with the original data points of wettability transformation of the pyramidal micro-nano composite structured surface that does not achieve super-hydrophobicity under the 100°C temperature-controlled aging strategy. The other steps remain unchanged, and the following can be obtained: Figure 7 The natural law curve of the original data of the wettability transition of the pyramidal micro-nano composite structured surface, the fitting prediction curve of the wettability transition and super-hydrophobicity based on the cubic spline numerical calculation principle, and the static contact angle result of the pyramidal micro-nano composite structured super-hydrophobic surface obtained under the fitting prediction aging treatment time (31.64h);

[0045] Analysis showed that within the aging time (31.64 hours) predicted by the cubic spline numerical calculation principle determined in the above process, the pyramidal micro-nano composite structured surface can achieve a superhydrophobic state and an extreme wettability state with a contact angle of approximately 169°, 168.983°. The fitting prediction error is 0.16% compared to the theoretical fitting prediction of 169.052659°. This also achieves the quantitative and precise modulation and prediction of the wettability transition and superhydrophobicity of the pyramidal micro-nano composite structured surface that has not yet achieved superhydrophobic properties through the combined control of femtosecond laser texturing and temperature-controlled aging.

[0046] Example 3, the wettability conversion and super-hydrophobicity preparation process in step 1) are replaced by a dip coating method and the independent variable in step 2) is replaced by the concentration of the low surface energy modification agent, as shown in FIG. Figure 1 By adaptively adjusting and executing the above steps in the process shown, quantitative modulation and prediction of wettability transformation and super-hydrophobicity acquisition under this preparation process can be achieved, and the effect is similar to that of Example 1.

[0047] Example 4, the wettability conversion and super-hydrophobicity preparation process in step 1) were replaced by a dip coating method and the independent variable in step 2) was replaced by a low surface energy modification time. Figure 1 By adaptively adjusting and executing the above steps in the process shown, quantitative modulation and prediction of wettability transformation and super-hydrophobicity acquisition under this preparation process can be achieved, and the effect is similar to that of Example 1.

[0048] Example 5, the preparation process of wettability transformation and super-hydrophobicity in step 1) is replaced by a process based on template-based composite nanoimprinting comprehensive control and the independent variable in step 2) is replaced by the corresponding dimensional characteristics of the obtained structure, such as the height of the cylindrical structure, etc., according to Figure 1By adaptively adjusting and executing the above steps in the process shown, quantitative modulation and prediction of wettability transformation and super-hydrophobicity acquisition under this preparation process can be achieved, and the effect is similar to that of Example 1.

Claims

1. A method for wettability transformation and superhydrophobicity quantitative modulation based on numerical calculation, characterized in that: The following steps are involved: 1) Determine the required wettability control and the preparation process procedures for obtaining superhydrophobic extreme wettability based on engineering requirements; 2) Determine the dependent and independent variables that influence wettability transition and superhydrophobicity realization based on the fabrication process specifications, i.e., determine the independent and dependent variables through quantitative and precise modulation and fitting prediction. The dependent variable is the static contact angle or rolling angle; the independent variables are the aging treatment time under the temperature-controlled aging strategy, and the concentration or modification time of the low-surface-energy modification agent under various dip-coating methods. 3) collecting raw data points of the infiltrative transition based on the dependent and independent variables established in step 2) and forming a corresponding infiltrative transition basic database; 4) Based on the establishment of a basic database of wettability transition, perform original fitting of the natural laws of wettability transition; 5) Based on step 4), the wettability transition is predicted by the fitting method selected based on numerical calculation, namely: 5.1) Using Matlab programming, we can obtain the fitting prediction curves based on the cubic spline numerical calculation principle and the least squares numerical calculation method respectively; 5.2) Determine whether the predicted fit is distorted based on whether the boundary conditions for wettability transition, i.e., contact angles and rolling angles that do not exceed 180° and are less than the critical limit under functional requirements, as well as the natural transition law, are met, and make corresponding adjustments. Specifically, if distortion occurs in the fitting prediction based on the cubic spline numerical calculation principle, remove accidental error points based on the slope gradient, and then re-fit and predict based on the wettability transition law based on the cubic spline numerical calculation principle until distortion is eliminated. Similarly, if distortion occurs in the fitting prediction based on the least squares numerical calculation principle, remove accidental error points while changing the highest-order parameter of the polynomial fitting. The error generated by the least squares numerical calculation fitting prediction should be minimized until distortion is eliminated. 6) When the two methods based on the above numerical calculation principle are fitted to the optimal state, a comparison based on the wettability fitting accuracy is performed to determine the final numerical calculation fitting prediction method; at the same time, quantitative and precise modulation and experimental verification of the wettability transition and superhydrophobicity achieved under this numerical calculation fitting prediction method are performed to meet engineering applications with specific functional requirements.

2. The method according to claim 1, wherein: The preparation process of step 1) includes wettability control and super-hydrophobicity realization process under temperature control aging strategy, wettability control and super-hydrophobicity realization process based on dip coating method, and wettability control and super-hydrophobicity realization process based on template method.

3. The method according to claim 1, wherein: The wettability transformation basic database in step 3) includes a two-dimensional mathematical model database and a multi-dimensional wettability transformation original database formed based on the response surface method.

4. The method according to claim 1, wherein: The fitting prediction method of wettability transition based on numerical calculation includes logical algorithms based on the cubic spline numerical calculation principle and logical algorithms based on the least squares numerical calculation principle implemented by any programming language or software, and also includes numerical calculation principles and methods for similar data fitting prediction implemented with the least squares method or cubic spline.

5. The method according to claim 1, wherein: The solutions to the distortion phenomenon in step 5.2) include elimination of accidental error points based on the slope gradient and repeated cyclic fitting of the prediction curve, as well as more in-depth distortion control and adaptive methods based on machine learning.

6. The method according to claim 1, wherein: The engineering technology applications of the wettability transition based on numerical calculation fitting prediction and the quantitative modulation method of superhydrophobicity include droplet transport based on wettability gradient and droplet operation based on different adhesion properties, as well as other engineering technology applications that include quantitative and precise modulation and prediction characteristics of wettability.

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