A device and method for synchronously measuring liquid surface tension and liquid-solid contact angle by temperature control

Abstract

The present invention discloses a device and method for synchronously measuring liquid surface tension and liquid-solid contact angle with temperature control. The liquid holding box to be tested is a box structure with an open top. The lower part of the liquid holding box to be tested is arranged in a water bath. The dynamometer is suspended with the output end of the driving mechanism. The output end of the driving mechanism can drive the dynamometer to move up and down. The solid hanging piece to be tested is suspended at the lower end of the dynamometer. The solid hanging piece to be tested is located above the liquid holding box to be tested. The laser radar rangefinder scanner is arranged on one side of the solid hanging piece to be tested. The laser output end on the laser radar rangefinder scanner is flush with the surface of the liquid to be tested in the liquid holding box to be tested. The laser radar rangefinder scanner can scan the contact part when the solid hanging piece to be tested contacts the liquid to be tested. The present invention has the characteristics of being able to control the test temperature, synchronously measure the liquid surface tension and the liquid-solid contact angle, simple structure, high precision, good repeatability, wide application range and low cost.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical measurement, and in particular relates to a device and a method for synchronously measuring liquid surface tension and liquid-solid contact angle by temperature control. Background Art

[0002] Wetting is a common physical phenomenon, but the degree of wetting of solids by liquids is affected by the type, properties and surface conditions of the liquids and solids. In order to characterize the wetting degree of different liquids on different solids and to further explore the wetting mechanism between liquids and solids, scholars have proposed the concepts of surface tension and contact angle. Measuring the surface tension of different liquids and the contact angle between liquids and solids is very important for mastering the wettability, adhesion, lubricity and diffusivity between liquids and solids. According to the characteristics of different degrees of wetting between liquids and solids, many fields of modern disciplines such as energy, transportation, machinery, civil engineering, chemical engineering, textiles, nanomaterials, biology, and medicine have developed corresponding processes and products. For example, in mineral flotation, whether bubbles can successfully capture mineral particles depends on the wetting ability of suspended particles and liquid environment; in oil extraction, the different wetting properties of two fluids on solid walls are used to displace the liquid to drive the oil; super-hydrophobic nanostructure surface development; research on the ability of artificial biomaterials to infiltrate blood in biomedicine, etc.

[0003] In the field of highway engineering, the use of surface energy theory to evaluate the adhesion between aggregate and asphalt is increasingly accepted and respected by scholars, and the surface tension of liquids and the contact angle between liquids and solids are important parameters in surface energy theory. Related studies have shown that potholes, cracks, local subsidence, looseness and other diseases of asphalt pavement are all related to water damage, and the occurrence of water damage is due to the fact that water molecules are more likely to wet the aggregate surface than asphalt molecules. When the aggregate coated with asphalt is in a water environment for a long time, the water molecules contact and wet the aggregate molecules, replacing the adhesion of asphalt. Therefore, measuring the surface tension of different liquids and the contact angle between liquids and solids can effectively distinguish and evaluate the adhesion and surface energy between liquids and solids, and thus has important engineering significance for selecting more hydrophobic aggregates and more lithophilic asphalt.

[0004] At present, there are many methods for measuring liquid surface tension and liquid-solid contact angle, such as capillary rise method, maximum bubble pressure method, hanging ring method, hanging sheet method, drop shape method, drop weight or drop volume method, pull-off method, surface light scattering method, electromagnetic suspension method, oscillating jet method, capillary wave method, etc. Among them, the drop shape method is favored by people because of its simple principle, intuitive results, easy-to-master method, and precise instruments and equipment on the market. However, it also has the defects of very few types of liquids that can be measured, expensive instruments and equipment, high requirements for drop shape, high requirements for shockproof level, difficult to control test temperature, inability to directly measure surface tension γ, and weak measurement of viscous liquids. For this reason, many patents have proposed unique improved methods and optimized test devices based on this method, but most of them are based on image shooting and post-image processing technology to obtain the liquid-solid contact angle, and the accuracy is relatively low. At the same time, there are very few patents based on the hanging sheet method to study liquid surface tension and liquid-solid contact angle, and no advanced radar or ultrasonic ranging technology has been introduced.

[0005] The hanging sheet method is based on the measurement of liquid surface tension and liquid-solid contact angle, which has the advantages of simple principle, easy operation, temperature control, applicability to a variety of solutions, easy calculation of surface tension γ, and low requirements for external conditions. In the past, there were few instruments related to the hanging sheet method, most of which relied on imported equipment, and the price of these equipment was high, completely discarding the advantages of the hanging sheet method. At the same time, most equipment still uses image capture and post-image processing technology to measure the liquid-solid contact angle, which not only has low measurement accuracy, but is also extremely time-consuming and labor-intensive. Summary of the invention

[0006] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a device and method for temperature-controlled synchronous measurement of liquid surface tension and liquid-solid contact angle. The device has a simple structure and is easy to operate. It can simultaneously realize rapid and accurate measurement of the surface tension γ value and precise measurement of the liquid-solid contact angle, and does not require image collection and post-processing of the image.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] A device for synchronously measuring liquid surface tension and liquid-solid contact angle with temperature control comprises a water bath, a liquid holding box to be tested, a laser radar rangefinder scanner, a driving mechanism, a dynamometer and a solid hanging piece to be tested. The liquid holding box to be tested is a box structure with an open top, the lower part of the liquid holding box to be tested is arranged in the water bath, the dynamometer is suspended with the output end of the driving mechanism, the output end of the driving mechanism can drive the dynamometer to move up and down, the solid hanging piece to be tested is suspended at the lower end of the dynamometer, and the solid hanging piece to be tested is located above the liquid holding box to be tested; the laser radar rangefinder scanner is arranged on one side of the solid hanging piece to be tested, the laser output end on the laser radar rangefinder scanner is flush with the surface of the liquid to be tested in the liquid holding box to be tested, and the laser radar rangefinder scanner can scan the contact part when the solid hanging piece to be tested contacts the liquid to be tested.

[0009] The water bath is transparent, with an opening on the top surface of the water bath, an extension section downwardly provided on the inner edge of the opening, and a sealing connection between the upper end of the liquid holding box to be tested and the lower end of the extension section; a groove is provided from the top downwardly on one side of the extension section of the water bath, and the laser radar ranging scanner is arranged in the groove, and the laser emitting end of the laser radar ranging scanner is perpendicular to the extension section.

[0010] The solid hanging piece to be tested is in the shape of a rectangular parallelepiped, and two through holes are symmetrically opened at the upper end of the solid hanging piece to be tested. The solid hanging piece to be tested is suspended at the lower end of the dynamometer through the two through holes and a thin wire. The bottom surface of the solid hanging piece to be tested is in a horizontal state, and a number of horizontal marking lines are provided from top to bottom at the lower end of the solid hanging piece to be tested.

[0011] The bottom of the water bath is provided with a water outlet, and the top is provided with a water inlet; the water bath is also provided with a temperature control system for controlling the temperature of the liquid in the water bath.

[0012] The temperature control system includes a heater, a temperature sensor and a temperature controller. The heater and the temperature sensor are arranged in a water bath and are respectively used to heat the liquid in the water bath and to measure the temperature of the liquid in the water bath; the heater and the temperature sensor are both connected to the temperature controller.

[0013] The driving mechanism comprises a motor capable of forward and reverse rotation, the motor is connected to a motor controller, and the dynamometer is connected to the output shaft of the motor via a thin wire.

[0014] Two laser radar ranging scanners are arranged, and the two laser radar ranging scanners are arranged symmetrically about the solid hanging piece to be measured.

[0015] The utility model also includes a computer, which is connected to the laser radar ranging scanner.

[0016] The dynamometer adopts electronic digital display dynamometer.

[0017] A method for synchronously measuring liquid surface tension and liquid-solid contact angle by temperature control is performed by the device for synchronously measuring liquid surface tension and liquid-solid contact angle by temperature control of the present invention, and comprises the following process:

[0018] Allowing the liquid to be tested in the liquid containing box to reach a preset temperature;

[0019] Measure the weight of the solid hanging piece to be tested;

[0020] The solid hanging piece to be tested is lowered and immersed in the liquid to be tested. During the contact process between the solid hanging piece to be tested and the liquid to be tested, a laser radar ranging scanner is used to scan the contact part between the solid hanging piece to be tested and the liquid to be tested, and the measured value of the dynamometer is recorded at the same time; the infiltration curve is obtained according to the scanning result of the laser radar ranging scanner;

[0021] The contact angle between the liquid to be tested and the solid hanging piece to be tested is obtained using the wetting curve, and the surface tension of the liquid to be tested is obtained using the measured value of the dynamometer, the weight and size of the solid hanging piece to be tested.

[0022] The present invention has the following beneficial effects:

[0023] The device for synchronously measuring the surface tension of liquid and the liquid-solid contact angle of the present invention can control the temperature during measurement by setting a water bath box, so that the temperature of the liquid to be tested in the liquid holding box to be tested remains stable. Since the surface tension of the liquid is different at different temperatures, the contact angle between the liquid and the solid will also be affected. It is of great engineering significance and practical significance to be able to control the measurement of the surface tension and contact angle at different temperatures. The present invention drives the dynamometer to move up and down by a driving mechanism, and the dynamometer can be used to measure the surface tension of the solid hanging piece to be tested when it contacts the liquid to be tested; the laser radar ranging scanner can scan the contact part when the solid hanging piece to be tested contacts the liquid to be tested, and the laser radar ranging scanner can draw the ranging curve when scanning. According to the obtained ranging curve, the liquid-solid contact angle between the solid hanging piece to be tested and the liquid to be tested can be obtained, and the result of the liquid-solid contact angle is more accurate. As can be seen from the above, the present invention can synchronously measure the liquid-solid contact angle while testing the surface tension of the liquid, without the need to collect images and post-process the images. It solves the problem that there is currently no instrument that can perform synchronous testing of surface tension and contact angle. At the same time, the device for synchronously measuring liquid surface tension and liquid-solid contact angle by temperature control of the present invention is relatively simple in structure and relatively low in cost.

[0024] The method for temperature-controlled synchronous measurement of liquid surface tension and liquid-solid contact angle of the present invention is carried out using the above-mentioned device of the present invention. It can be seen from the above that the method can synchronously test the surface tension of the liquid and the liquid-solid contact angle without the need to collect images and post-process the images. The operation process is simple and the surface tension of the liquid and the liquid-solid contact angle at different temperatures can be measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a front schematic diagram of the device for synchronously measuring liquid surface tension and liquid-solid contact angle by temperature control of the present invention;

[0026] Figure 2 It is a side schematic diagram of the device for synchronously measuring liquid surface tension and liquid-solid contact angle by temperature control of the present invention;

[0027] Figure 3 It is a front schematic diagram of the solid hanging piece to be tested of the present invention;

[0028] Figure 4 It is a side schematic diagram of the solid hanging piece to be tested according to the present invention.

[0029] In the figure: 1 is a solid hanging piece to be tested; 1-1 is a marking line; 2 is a force gauge; 3 is a thin line; 4 is a liquid to be tested; 5 is a motor; 6 is a motor controller; 7 is a computer; 8 is a laser radar ranging scanner; 9 is a box handle; 10 is a power supply; 11 is a temperature controller; 12 is a heater; 13 is a support column; 14 is a box for holding the liquid to be tested; 15 is a connecting bolt; 16 is a water bath, 16-1 is an opening, 16-2 is an extension section, and 16-3 is a groove. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and the following embodiments. It should be understood that the accompanying drawings and the following embodiments are only used to illustrate the present invention rather than to limit the present invention.

[0031] The purpose of the present invention is to break the method limitations of the droplet shape method, start from a new perspective, make full use of existing advanced technologies, give full play to the advantages of the hanging plate method, achieve controllable temperature in the range of 0 to 100°C, rapid and accurate determination of the surface tension γ value, precise determination of the liquid-solid contact angle, and good test repeatability, applicability to a variety of liquids and low cost. A method and device for synchronously determining the liquid surface tension and the liquid-solid contact angle with temperature control based on the hanging plate method are provided, and corresponding calculation and testing methods are given.

[0032] Reference Figure 1 and Figure 2The device for synchronously measuring the surface tension of liquid and the liquid-solid contact angle with temperature control of the present invention comprises a water bath 16, a liquid holding box 14 to be tested, a laser radar ranging scanner 8, a driving mechanism, a dynamometer 2 and a solid hanging piece 1 to be tested. The liquid holding box 14 to be tested is a box structure with an open top. The lower part of the liquid holding box 14 to be tested is arranged in the water bath 16. The dynamometer 2 is suspended from the output end of the driving mechanism. The output end of the driving mechanism can drive the dynamometer 2 to move up and down. The solid hanging piece 1 to be tested is suspended from the lower end of the dynamometer 2. The solid hanging piece 1 to be tested is located above the liquid holding box 14 to be tested; the laser radar ranging scanner 8 is arranged on one side of the solid hanging piece 1 to be tested. The laser output end of the laser radar ranging scanner 8 is flush with the surface of the liquid 4 to be tested in the liquid holding box 14 to be tested. The laser radar ranging scanner 8 can scan the contact part when the solid hanging piece 1 to be tested contacts the liquid 4 to be tested.

[0033] As a preferred embodiment of the present invention, the water bath 16 is transparent, and an opening 16-1 is provided on the top surface of the water bath 16. An extension section 16-2 is provided downwardly at the inner edge of the opening 16-1, and the upper end of the liquid holding box 14 to be tested is sealed with the lower end of the extension section 16-2; the water bath 16 is provided with a groove 16-3 from the top downward on one side of the extension section 16-2, and the laser radar ranging scanner 8 is arranged in the groove 16-3, and the laser emitting end of the laser radar ranging scanner 8 is perpendicular to the extension section 16-2.

[0034] As a preferred embodiment of the present invention, refer to Figure 3 and Figure 4 The solid hanging piece 1 to be tested is in the shape of a rectangular parallelepiped, and two through holes are symmetrically opened at the upper end of the solid hanging piece 1 to be tested. The solid hanging piece 1 to be tested is suspended at the lower end of the dynamometer 2 through the two through holes and a thin wire 3. The bottom surface of the solid hanging piece 1 to be tested is in a horizontal state, and a plurality of horizontal marking lines are arranged at the lower end of the solid hanging piece 1 to be tested from top to bottom.

[0035] As a preferred embodiment of the present invention, a water outlet is provided at the bottom of the water bath 16 and a water inlet is provided at the top; the water bath 16 is also provided with a temperature control system for controlling the temperature of the liquid in the water bath 16 .

[0036] As a preferred embodiment of the present invention, Figure 1 and Figure 2 As shown, the temperature control system includes a heater 12, a temperature sensor and a temperature controller 11. The heater 12 and the temperature sensor are arranged in a water bath 16, and are respectively used to heat the liquid in the water bath 16 and to measure the temperature of the liquid in the water bath 16; the heater 12 and the temperature sensor are both connected to the temperature controller 11.

[0037] As a preferred embodiment of the present invention, Figure 1 and Figure 2As shown, the driving mechanism includes a motor 5 capable of forward and reverse rotation, a motor controller 6 is connected to the motor 5, and the dynamometer 2 is connected to the output shaft of the motor 5 via a thin wire.

[0038] As a preferred embodiment of the present invention, Figure 1 As shown, two laser radar ranging scanners 8 are provided, and the two laser radar ranging scanners 8 are symmetrically arranged with respect to the solid hanging piece 1 to be measured.

[0039] As a preferred embodiment of the present invention, the device for temperature-controlled synchronous measurement of liquid surface tension and liquid-solid contact angle of the present invention also includes a computer 7, which is connected to a laser radar ranging scanner 8. The computer 7 can control the operation of the laser radar ranging scanner 8 and obtain and display the data obtained by the laser radar ranging scanner 8.

[0040] As a preferred embodiment of the present invention, the dynamometer 2 is an electronic digital dynamometer.

[0041] The method for synchronously measuring liquid surface tension and liquid-solid contact angle by temperature control of the present invention is carried out by the device for synchronously measuring liquid surface tension and liquid-solid contact angle by temperature control of the present invention, and comprises the following process:

[0042] The liquid to be tested 4 in the liquid to be tested storage box 14 reaches a preset temperature;

[0043] Measuring the weight of the solid hanging piece 1 to be tested;

[0044] The solid hanging piece 1 to be tested is lowered and immersed in the liquid 4 to be tested. During the contact process between the solid hanging piece 1 to be tested and the liquid 4 to be tested, the contact part between the solid hanging piece 1 to be tested and the liquid 4 to be tested is scanned by using a laser radar ranging scanner 8, and the measurement value of the dynamometer 2 is recorded at the same time; the wetting curve is obtained according to the scanning result of the laser radar ranging scanner 8;

[0045] The contact angle between the liquid to be tested and the solid hanging piece 1 to be tested is obtained using the wetting curve, and the surface tension of the liquid to be tested is obtained using the measured value of the dynamometer 2 and the weight and size of the solid hanging piece 1 to be tested.

[0046] Example

[0047] Reference Figure 1The water bath 16 in the device for synchronously measuring liquid surface tension and liquid-solid contact angle by temperature control of this embodiment is the main bearing structure. The overall structure of the water bath 16 is made of tempered glass and is transparent. A support column 13 is provided at the bottom of the water bath 16, and a box handle 9 is provided on the outside. Four support columns 13 are in the middle of the tempered glass box 16, the bottom of the support column 13 is connected to the bottom of the water bath 16, and the top of the support column 13 is connected to the bottom of the liquid holding box 14 to be tested. The support column 13 bears part of the weight of the liquid holding box 14 to be tested. The liquid holding box 14 to be tested is made of copper, which has good thermal conductivity and is conducive to the heating of the liquid 4 to be tested and the stabilization of the temperature. The handle 9 of the box body is convenient for carrying and moving the entire device; the top surface of the water bath box 16 is provided with an opening 16-1, and the inner edge of the opening 16-1 is provided with an extension section 16-2 downwardly, and the upper end of the liquid holding box 14 to be tested is connected to the lower end of the extension section 16-2 by a connecting bolt 15 and is sealed between the extension section 16-2 to prevent the liquid in the water bath box 16 from entering the liquid holding box 14 to be tested and interfering with the test results; the water bath box 16 is provided with a groove 16-3 from the top downwardly on one side of the extension section 16-2, and the laser radar ranging scanner 8 is arranged in the groove 1 In 6-3, the laser emitting end of the laser radar range scanner 8 is perpendicular to the extension section 16-2; two laser radar range scanners 8 are provided, and the two laser radar range scanners 8 are symmetrically arranged about the solid hanging piece 1 to be measured; the laser radar range scanner 8 is connected to the computer 7 through a data line; the driving mechanism includes a motor 5 that can rotate forward and reverse, the motor 5 is connected to a motor controller 6, and the dynamometer 2 is connected to the output shaft of the motor 5 through a thin wire 3; a bracket for installing the motor 5 is provided on the water bath box 16, and the motor 5 is located above the liquid holding box to be measured. The motor controller 6 can control the motor 5 to rotate forward or reverse. The thin wire 3 is used to suspend the solid hanging piece 1 to be tested and the dynamometer 2, and the dynamometer 2 is used to read the tension value of the solid hanging piece 1 to be tested after being immersed in the liquid 4 to be tested; the temperature control system includes a heater 12, a temperature sensor and a temperature controller 11, and the heater 12 and the temperature sensor are arranged in a water bath 16, and are respectively used to heat the liquid in the water bath 16 and to measure the temperature of the liquid in the water bath 16; the heater 12 and the temperature sensor are both connected to the temperature controller 11. The heater 12 extends into the water bath 16.

[0048] It should be noted that the tempered glass box 16 of the water bath is provided with a liquid inlet at the top and a liquid outlet at the bottom. During the test, the liquid inlet and the liquid outlet are sealed with a rubber plug; the laser radar ranging scanner 8 is the main equipment for measuring the contact angle between liquid and solid. It has a fast scanning function. When the solid hanging piece 1 to be tested is immersed in the liquid 4 to be tested to the 3 marking lines on it, the laser radar ranging scanners 8 on both sides are turned on at the same time for fast scanning; the motor 5 adopts a micro forward and reverse speed-controlled motor, and the motor controller 6 provides power for the motor 5 and controls its opening and closing and forward and reverse rotation. The motor controller 6 should be set to 2 Buttons, one controls the start and stop of the motor 5, and the other controls the forward and reverse rotation of the motor 5 (press once for forward rotation, and press once again for reverse rotation); the temperature controller 11 can control the heating and insulation temperature of the heater 12 according to the temperature information collected by the temperature sensor. The temperature controller 11 is provided with an electronic display screen and at least two buttons (i.e., an upward temperature adjustment button and a downward temperature adjustment button), which can adjust the temperature of the liquid in the water bath, and can automatically start heating or insulation according to the set temperature. The power supply connected to it is 220V AC, and the power supply has a switch to control the power-on status.

[0049] The dynamometer 2 is a digital display dynamometer, the liquid holding box 14 is made of a copper plate of 1-2 mm, and a mark is made inside the liquid holding box 14 at 100 mm from the inner bottom surface so as not to affect the radar scanning. The liquid holding box 14 can hold emulsified asphalt, color paint, ink and other liquids, and the liquid level of the liquid is controlled to always be at the designated box mark. The support column 13 is a tempered glass column or metal column with a diameter of 10 mm and a height of 150 mm. The thin wire 3 is a thin and soft metal wire with a diameter of 1mm. The length of the thin wire connected to the upper part of the electronic digital dynamometer should be sufficient to suspend the electronic digital dynamometer over 20mm from the motor. The length of the thin wire connected to the lower part of the electronic digital dynamometer should be able to control the bottom surface of the solid hanging piece 1 to be tested to be at least 2mm away from the liquid surface to be tested, and can bear the weight of the electronic digital dynamometer and the solid hanging piece to be tested; the solid hanging piece to be tested is a rectangular structure with a length, width and height of 10mm×2mm×20mm. There are two circular holes with a diameter of 1.5mm at 4mm from the top surface, and the spacing between the circular holes is 3mm. After the thin wire is inserted, it is connected to the dynamometer to form a stable triangular shape, and three marking lines are made across the entire length of the hanging piece at 1mm, 3mm and 5mm from the bottom surface of the hanging piece respectively; the electronic digital dynamometer should have the function of displaying the tension value with an accuracy of at least 0.01N and setting the tension to zero; the solid of the solid hanging piece to be tested can be materials such as rock, metal and rubber. The motor 5 should satisfy the requirement that the thin wire can rise or fall at a speed of 2mm / min; the power supply of the motor 5 adopts a DC rechargeable power supply, which can be a 12V or 24V low-voltage power supply. The length, width and height of the outer dimensions of the laser radar ranging scanner 8 are within 110mm×70mm×80mm, the minimum range should be within 150mm, the single ranging time is within 1ms, the ranging resolution is within 0.5mm, the scanning frequency is above 10Hz, the scanning angle range is adjustable, the angle resolution is less than 1°, and the working environment temperature should be above 50°C. If the temperature of the heated liquid is high, heat dissipation measures can be taken. Since the infiltration height of the liquid on the solid is small, the rotation angle of the laser radar ranging scanner 8 is generally within ±2°, which is basically perpendicular to the extension section 16-2, so the refraction problem of the tempered glass can be ignored. In addition, in order to avoid the influence of the refractive index to a greater extent, the thickness of the tempered glass slightly larger than the size range of the laser head (such as 10mm×10mm) facing the laser head of the laser radar ranging scanner 8 can also be thinned to about 1mm, and the thickness needs to be thinned from the side of the laser radar ranging scanner, and the inner wall of the liquid tank to be measured needs to be smooth. If you want to completely avoid the influence of the glass refractive index, you can drill a hole in the tempered glass facing the laser head, the hole size needs to be slightly larger than the size range of the laser head (such as 10mm×10mm), and paste or set a transparent thin plastic film.

[0050] The method for temperature-controlled synchronous measurement of liquid surface tension and liquid-solid contact angle of this embodiment comprises the following steps:

[0051] 1. Make a solid hanging piece 1 to be tested with a size of 10mm×2mm×20mm, and punch two round holes with a diameter of 1.5mm at 4mm on its top surface, with a spacing of 3mm. Care should be taken to avoid the thin piece from breaking, otherwise it should be remade, and then inserted with a thin wire 3, and hung on an electronic digital dynamometer (set the value of the dynamometer to zero before hanging, and the electronic digital dynamometer can use an EP brand NK / SF digital push-pull dynamometer), ensure that when the thin wire 3 is lifted, the lower part of the thin wire 3 is in a triangular shape, and the bottom surface of the solid hanging piece 1 to be tested is horizontal and the side is vertical, and then record the tension G at this time;

[0052] 2. Open the liquid inlet on the top of the water bath 16, add water to the bottom of the groove where the laser radar range scanner 8 is located, and then add the liquid to be tested 4 to the mark 100mm away from the inner bottom surface of the liquid to be tested container 14. When the liquid to be tested 4 is added close to the mark, use a rubber dropper to titrate;

[0053] 3. Debug the running condition of motor 5 (Zhengke brand ZGB37RG model DC micro low-speed forward and reverse adjustable speed motor) and the working condition of motor controller 6, and ensure the accurate control of the buttons of motor controller 6. If both are running well, suspend the bottom surface of the solid hanging piece 1 to be tested 2mm away from the liquid surface of the liquid 4 to be tested, and make the motor 5 in the power-on state. Otherwise, check and solve the existing problems to ensure that the requirements are met before testing;

[0054] 4. Debug the working conditions of the computer 7 and the laser radar ranging scanners 8 (Slam brand LIDAR laser A1 radar 360° scanning ranging ROS robot slam, with control drawing function) on both sides of the solid hanging piece 1 to be tested, and wait for them to draw the same ranging curve to prove that they are running well. Otherwise, find out the cause and solve the problem until the requirements are met, and then put both of them in the power-on state for testing and control;

[0055] 5. Debug the heater 12, the temperature controller 11 (KEYU-QIAN temperature-controlled 304 stainless steel heating rod) and the AC power supply 10 to ensure that the heater 12 can work normally, the temperature controller 11 can set the temperature well, and automatically start the heating or insulation system. The AC power supply 10 uses 220V AC and has a switch to control the power-on status. Otherwise, find out the cause and solve the problem until the requirements are met, then set it to the test temperature and start the heater 12 for heating;

[0056] 6. Use an infrared temperature measuring gun (Xima brand AS model infrared handheld temperature measuring gun) to measure the temperature of the liquid 4 to be tested. After reaching the standard temperature, start the motor 5 to lower the solid hanging piece 1 to be tested. When the liquid level of the liquid 4 to be tested reaches the 3 marking lines of the solid hanging piece 1 to be tested, turn on the laser radar range scanner 8 to scan, and draw the infiltration curve on the computer. At the same time, read and record the reading of the electronic digital display dynamometer 2. When the measurement of the 3 marking lines is completed, press the reverse button of the motor controller 6 to measure the infiltration curve and tension value at the 3 marking lines when exiting again, and then turn off the motor power supply to stop heating;

[0057] 7. Perform nonlinear fitting on the wetting curves drawn by the two laser radar ranging scanners 8 to obtain the fitting equation y=f(x), and find the first derivative y′=f′(x). Calculate y′ when x=0 to obtain y′=f′(0)=tanθ. If the error of f′(0) obtained by the two laser radar ranging scanners is within 1%, and the error of the f′(0) parameter measured when the lines are marked at 3 locations should be within 0.1%, then take the average of these f′(0) as the final liquid-solid contact angle θ. Otherwise, find and solve the cause and re-measure. For example, in one measurement and fitting, the following equation is obtained:

[0058] y=-2.963x 3 +41.758x 2 -193.7x+301.25

[0059] Then taking its first derivative we can get:

[0060] y′=-2.963x 3 +41.758x 2 -193.7

[0061] When x = 0, y′ = -193.7 = arctanθ, then the liquid-solid contact angle θ = 89.7°;

[0062] 8. When testing the surface tension of the liquid, first read the gravity value of the hanging piece, recorded as G, and then read the tension value of the electronic digital dynamometer when the liquid surface is 1mm, 3mm and 5mm away from the bottom of the hanging piece, respectively F1, F2, F3, and the corresponding immersion areas are A1, A2, A3. The tension value F is the product of the liquid surface tension γ, the immersion area A and the buoyancy F of the hanging piece. f Joint decision means:

[0063] F=G+γ*AF f

[0064] Different liquids to be tested have different densities ρ. For the same liquid, the hanging pieces with different immersion depths have different immersion volumes, corresponding to V1, V2, and V3. According to the following formula

[0065] F f =ρgV

[0066] It can be seen that the corresponding buoyancy is F f1 、F f2 、F f3 , then the corresponding surface tension values ​​calculated when the liquid surface is 1mm, 3mm and 5mm away from the bottom of the hanging piece are:

[0067]

[0068]

[0069]

[0070] Since γ1, γ2, and γ3 are all surface tension values ​​of the liquid, the surface tension of the liquid should be the average of the three, that is:

[0071]

[0072] The present invention has the following advantages:

[0073] 1. Ability to control the temperature during measurement. The surface tension of liquid varies at different temperatures, which will also affect the contact angle between liquid and solid. Being able to control the measurement of surface tension and contact angle at different temperatures has great engineering and practical significance.

[0074] 2. It can simultaneously test the surface tension of liquid and the contact angle between liquid and solid. Currently, few instruments can simultaneously test surface tension and contact angle, and the few instruments that can simultaneously test both are relatively expensive;

[0075] 3. The device is designed based on the hanging sheet method which has many advantages. The hanging sheet method has the advantages of simple principle, relatively simple operation, controllable temperature, applicable to a variety of solutions, easy calculation of surface tension γ and low requirements for external conditions. At present, most test instruments rely on the drop shape method, and there are few instruments relying on the hanging sheet method;

[0076] 4. Wide range of applications. It can accurately measure the surface tension of various liquids, such as emulsified asphalt, color paint, ink and other liquids, and can accurately measure the contact angle between various liquids and various solids. The types of solids that can be measured include rocks, metals, rubber and other materials;

[0077] 5. High measurement accuracy. The electronic digital dynamometer should have a displayed tension value accuracy of at least 0.01N, the calculated surface tension accuracy of 0.01N / m, the laser radar ranging scanner ranging resolution within 0.5mm, and the calculated contact angle error is small, with an accuracy of 0.1°.

[0078] 6. The measurement has high stability, good repeatability, fast measurement speed, relatively simple principle and structure, easy to master, low cost, and the cost can be basically controlled within 2,000 yuan.

[0079] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structural transformation made by using the contents of the present invention description and drawings, or directly or indirectly applied in related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A device for synchronously measuring liquid surface tension and liquid-solid contact angle under temperature control, characterized in that: The invention comprises a water bath (16), a liquid storage box (14), a laser radar distance measuring scanner (8), a driving mechanism, a dynamometer (2) and a solid hanging piece (1) to be tested. The liquid storage box (14) to be tested is a box structure with an open top. The lower part of the liquid storage box (14) to be tested is arranged in the water bath (16). The dynamometer (2) is suspended from the output end of the driving mechanism. The output end of the driving mechanism can drive the dynamometer (2) to move up and down. The solid hanging piece (1) to be tested is suspended from the lower end of the dynamometer (2). The solid hanging piece (1) to be tested is located above the liquid storage box (14). The laser radar distance measuring scanner (8) is arranged on one side of the solid hanging piece (1) to be tested. The laser output end of the laser radar distance measuring scanner (8) is flush with the surface of the liquid (4) to be tested in the liquid storage box (14). The laser radar distance measuring scanner (8) can scan the contact part when the solid hanging piece (1) to be tested contacts the liquid (4). The water bath box (16) is transparent, and an opening (16-1) is provided on the top surface of the water bath box (16). An extension section (16-2) is provided downwardly at the inner edge of the opening (16-1), and the upper end of the liquid storage box (14) to be tested is sealedly connected to the lower end of the extension section (16-2). The water bath box (16) is provided with a groove (16-3) from the top downwardly on one side of the extension section (16-2), and the laser radar ranging scanner (8) is arranged in the groove (16-3), and the laser emitting end of the laser radar ranging scanner (8) is perpendicular to the extension section (16-2); The solid hanging piece (1) to be tested is in the shape of a rectangular parallelepiped, and two through holes are symmetrically opened at the upper end of the solid hanging piece (1) to be tested. The solid hanging piece (1) to be tested is suspended at the lower end of the dynamometer (2) through the two through holes and the thin wire (3). The bottom surface of the solid hanging piece (1) to be tested is in a horizontal state, and a plurality of horizontal marking lines are arranged at the lower end of the solid hanging piece (1) to be tested from top to bottom.

2. The device for synchronously measuring liquid surface tension and liquid-solid contact angle under temperature control according to claim 1, characterized in that: The water bath (16) is provided with a water outlet at the bottom and a water inlet at the top; the water bath (16) is also provided with a temperature control system for controlling the temperature of the liquid in the water bath (16).

3. The device for synchronously measuring liquid surface tension and liquid-solid contact angle under temperature control according to claim 2, characterized in that: The temperature control system comprises a heater (12), a temperature sensor and a temperature controller (11); the heater (12) and the temperature sensor are arranged in a water bath (16) and are respectively used to heat the liquid in the water bath (16) and to measure the temperature of the liquid in the water bath (16); and the heater (12) and the temperature sensor are both connected to the temperature controller (11).

4. The device for synchronously measuring liquid surface tension and liquid-solid contact angle under temperature control according to claim 1, characterized in that: The driving mechanism comprises a motor (5) capable of forward and reverse rotation, the motor (5) being connected to a motor controller (6), and the dynamometer (2) being connected to an output shaft of the motor (5) via a thin wire.

5. The device for synchronously measuring liquid surface tension and liquid-solid contact angle under temperature control according to claim 1, characterized in that: Two laser radar ranging scanners (8) are provided, and the two laser radar ranging scanners (8) are symmetrically arranged with respect to the solid hanging piece (1) to be measured.

6. The device for synchronously measuring liquid surface tension and liquid-solid contact angle under temperature control according to claim 1, characterized in that: It also includes a computer (7), which is connected to the laser radar ranging scanner (8).

7. The device for synchronously measuring liquid surface tension and liquid-solid contact angle under temperature control according to claim 1, characterized in that: The dynamometer (2) adopts an electronic digital display dynamometer.

8. A method for synchronously measuring liquid surface tension and liquid-solid contact angle by temperature control, characterized in that: The method is carried out by using the device for synchronously measuring the surface tension of liquid and the liquid-solid contact angle with temperature control as described in any one of claims 1 to 7, comprising the following process: Allowing the liquid to be tested (4) in the liquid to be tested storage box (14) to reach a preset temperature; Measuring the weight of the solid hanging piece (1) to be tested; The solid hanging piece (1) to be tested is lowered and immersed in the liquid (4) to be tested. During the contact process between the solid hanging piece (1) to be tested and the liquid (4) to be tested, a laser radar ranging scanner (8) is used to scan the contact portion between the solid hanging piece (1) to be tested and the liquid (4) to be tested, and the measurement value of the force gauge (2) is recorded at the same time; and an infiltration curve is obtained according to the scanning result of the laser radar ranging scanner (8); The contact angle between the liquid to be tested and the solid hanging piece (1) to be tested is obtained using the wetting curve, and the surface tension of the liquid to be tested is obtained using the measured value of the dynamometer (2) and the weight and size of the solid hanging piece (1) to be tested.

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