CN209432679U - Measuring device for measuring the adhesion force between solid-liquid interface under electric field - Google Patents

Abstract

The utility model discloses the measuring devices of adhesion strength between solid liquid interface under a kind of measurement electric field, comprising: transparent plastic operation cabinet, horizontal base, laser sensor, electricity driving displacement platform, cantilever beam, high speed camera, support frame, power supply and data control processing terminal.In measurement process, with the slow movement of electricity driving displacement platform, due to the effect of cantilever beam and the adhesion strength of drop, cantilever beam deforms, the specific value that cantilever beam deformation in experiment is recorded by laser sensor, can calculate the adhesion strength under electric field between solid-liquid.Meanwhile high-speed camera shoots whole experiment process, records upper and lower surface contact angle and the variation of contact area of drop.The measuring system has the characteristics that easy to operate, low in cost, applied widely, measurement accuracy is high, is well positioned to meet the requirement of adhesion strength between solid liquid interface under measurement electric field.

Description

Measuring device for measuring the adhesion force between solid-liquid interface under electric field

technical field

The utility model relates to a measuring device for measuring the adhesion force of a solid-liquid interface under an electric field, in particular to measuring the tiny deformation of a cantilever beam by using a laser, and calculating the solid-liquid interface adhesion force under an electric field through the relationship between the deformation of the cantilever beam and the behavior of the solid-liquid interface. Adhesion at the liquid interface.

Background technique

Solid-liquid interface behavior plays an extremely important role in production and life. By studying the behavior of the solid-liquid interface, the functions of anti-fouling, anti-icing, anti-adhesion, self-cleaning, and adsorption can be realized in the fields of aerospace, shipbuilding, textiles, construction, and environmental protection. Therefore, the study of solid-liquid interface behavior can not only promote the development of basic science, but also greatly promote the improvement of scientific and technological level. With the continuous development of science and technology and the expansion of market demand, active control of solid-liquid interface behavior has become a future development trend and research hotspot. The previous research mainly met the requirements by changing the properties of solid or liquid droplets, such as changing the behavior of the solid-liquid interface to make the solid surface achieve a super-hydrophilic or super-hydrophobic state to meet the requirements, which belongs to quasi-static control of the behavior of the solid-liquid interface. With the development of automation and informatization, it is imperative to dynamically control the behavior of solid-liquid interface. Active control of solid-liquid interface behavior by voltage is the most widely used method among various active control methods. For example, microfluidic separation, merging and transportation can be achieved by controlling microfluidics with voltage, which has been widely used in analytical chemistry, biomedicine, food and other fields. However, with the further development of the integration and miniaturization of microfluidic control equipment, the behavior of the solid-liquid interface on the microscopic scale becomes more complex, which has a great impact on the stability and reliability of the system. The laboratory is moving towards the technical bottleneck of application. Therefore, the in-depth study of the solid-liquid interface behavior under the electric field has become a hot and difficult point in current research.

The adhesion force at the solid-liquid interface is the most important force at the solid-liquid interface and plays a leading role in the behavior of the solid-liquid interface. At present, the behavior of the solid-liquid interface at the microscopic scale is usually studied by using inclined plate devices, atomic force microscopes, surface force meters and other scientific research equipment to study the adhesion. The inclined plate device mainly obtains the solid-liquid interface adhesion force by observing the movement law of the liquid droplet on the inclined plate under the action of gravity. This method is simple to operate and the data is intuitive, but the measurement accuracy is very low. The tested droplets are limited by various factors, such as the droplet size decreases, the solid-liquid interface adhesion force is too large, and the droplet will not occur on the inclined plate. Movement, will prevent the test from being completed. Therefore, when the droplet is in the microscopic scale, the adhesion force of the solid-liquid interface is usually tested by precision instruments such as atomic force microscope and surface force meter. The principle of this type of instrument is to touch the solid surface covered with water film through a micro-probe, and reflect the adhesion behavior of the solid-liquid interface through the electrical signal when the probe contacts and separates from the solid surface. The data obtained by this measurement method is accurate, but the data does not reflect the complete solid-liquid interface behavior, but a coupling behavior between the solid-liquid-solid three-phase, which is quite different from the actual working conditions. In addition, atomic force microscopes, surface force meters, etc. are precision instruments, which put forward extremely high requirements for operators, test environment, test process, test samples, etc. Small change factors will cause large experimental errors. Not only that, the measurement of the solid-liquid interface adhesion force under the electric field needs to introduce the electric field force and the liquid phase environment, which will reduce the test accuracy of the instrument and may cause damage to the instrument. Therefore, there is an urgent need to develop a method and device that is easy to operate, high in measurement accuracy, and applicable to electric field and liquid phase environments, so as to accurately and quickly measure the adhesion force between the solid-liquid interface under the electric field.

Utility model content

An object of the present invention is to solve at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described hereinafter.

In order to achieve these purposes and other advantages according to the utility model, a kind of measuring device for measuring the adhesion force between the solid-liquid interface under the electric field is provided, comprising:

Transparent plastic operation cabinet;

A horizontal base, which is set in a transparent plastic operation cabinet;

Electric displacement platform, which is vertically arranged on the horizontal base;

A horizontal copper plate, which is arranged on a horizontal base; a standard electrowetting test sample on a medium is bonded to the top of the horizontal copper plate; wherein, droplets are added to the standard electrowetting test sample on the medium;

L-shaped cantilever beam, one end of which is connected to the sliding block of the electric displacement platform, and the other end is vertically facing the electrowetting standard experimental sample on the medium, and the vertical end of the L-shaped cantilever beam is connected to the droplet through the movement of the electric displacement platform. the upper end contact;

The laser sensor is vertically arranged directly above the electrowetting standard experimental sample on the medium through the support frame and is aligned with the vertical end of the L-shaped cantilever to photograph the displacement of the L-shaped cantilever;

A high-speed camera; it is arranged on a horizontal base, and the high-speed camera is positioned on the side of the electrowetting standard experimental sample on the medium to photograph the contact situation between the droplet and the vertical end of the L-shaped cantilever beam;

The power supply is arranged on the horizontal base, the positive pole of the power supply is electrically connected to the L-shaped cantilever beam through the wire I, and the negative pole of the power supply is electrically connected to the horizontal copper plate through the wire II;

The data control processing terminal is located outside the transparent plastic operation cabinet, and the data control processing terminal is electrically connected with the electric displacement platform, the laser sensor, and the high-speed camera respectively.

Preferably, the electrowetting standard test sample on the medium is bonded above the horizontal copper plate with conductive gel; the L-shaped cantilever beam is an L-shaped pure copper tube with an outer diameter of 0.5mm and an inner diameter of 0.25mm ; One end of the L-shaped cantilever beam is connected to the sliding block of the electric displacement platform through a conductive gel.

Preferably, the standard experimental sample of electrowetting on a medium includes: a silicon wafer, an insulating layer plated on the silicon wafer, and a hydrophobic layer coated and dried on the insulating layer.

Preferably, the insulating layer is a 200-400nm SiO ₂ coating, and the hydrophobic layer is a Teflon layer.

Preferably, the support frame includes a vertical support frame and a horizontal support frame that are vertically connected with the same structure; the structure of the support frame includes:

The fixed end I and the fixed end II arranged in parallel are connected by two parallel linear guide rails;

a sliding block, which is slidably connected to two parallel linear guide rails;

The ball screw is connected to the fixed end Ⅰ, the sliding block and the fixed end Ⅱ in turn by threads;

Wherein, the fixed end I of the vertical support frame is connected to the horizontal base, and the fixed end I of the horizontal support frame is connected to the sliding block of the vertical support frame; the laser sensor is connected to the sliding block of the horizontal support frame. Move the block on.

Preferably, the electric displacement platform is electrically connected to the data control processing terminal through the displacement platform data output port; the laser sensor is electrically connected to the data control processing terminal through the laser data output port; the high-speed camera is output through the image data The port is electrically connected to the data control processing terminal.

The model of the manufacturer Beijing Jiangyun Photoelectric Technology Co., Ltd. of the electric displacement platform adopted by the utility model is Y200TA75.

The utility model at least includes the following beneficial effects:

(1) The method of the utility model does not need expensive experimental equipment, is simple to calculate, has high precision, and has extremely high practical value.

(2) The manufacture of the cantilever beam and the sample sample is simple and low in cost, and the experimenter can flexibly adjust it according to the actual situation.

(3) The instrument can realize the measurement of various forces through simple adjustments to meet the electric field and liquid phase test environments. The test method is simple, the operability is strong, the experimental results are accurate, and the experimental results are highly repeatable.

(4) The experimental process can be carried out at normal temperature and normal pressure, without the need for special experimental environments such as dust-free and constant temperature; at the same time, the detection time is short, and a set of experiments can be completed in 5 to 7 minutes, which can greatly improve the experimental efficiency.

Other advantages, objectives and features of the utility model will partly be embodied through the following description, and partly will be understood by those skilled in the art through the research and practice of the utility model.

Description of drawings:

Fig. 1 is the overall system structure schematic diagram of the measuring device of the utility model measuring the adhesive force between the solid-liquid interface under the electric field;

Fig. 2 is the structural representation of the electrowetting standard experiment sample on the medium described in the utility model;

Fig. 3 is the structural representation of the support frame described in the utility model;

Fig. 4 is the schematic diagram of the change of the L-shaped cantilever before and after the experiment of the utility model measuring the adhesion force between the solid-liquid interface under the electric field;

Fig. 5 is a relationship diagram between the displacement and time of the L-shaped cantilever beam of the measuring device for measuring the adhesion force between the solid-liquid interface under the electric field of the utility model.

Detailed ways:

The utility model will be described in further detail below in conjunction with the accompanying drawings, so that those skilled in the art can implement it by referring to the description.

It should be understood that terms such as "having", "comprising" and "including" as used herein do not entail the presence or addition of one or more other elements or combinations thereof.

The utility model designs a measuring device for measuring the adhesion force of a solid-liquid interface under an electric field. During the measurement process using this measuring device, with the slow movement of the electric displacement platform, the L-shaped cantilever deforms due to the adhesion force between the L-shaped cantilever and the droplet, and the L-shaped cantilever in the experiment is recorded by the laser sensor. The specific value of beam deformation can calculate the adhesion force between solid and liquid. At the same time, a high-speed camera photographed the entire experimental process, recording the changes in the contact angle and contact area of the upper and lower surfaces of the droplet. In addition, the L-shaped cantilever beam can also use materials with different mechanical properties according to the actual situation of the experiment, which can further improve the accuracy of the experiment. The measurement system has the characteristics of simple operation, low cost, wide application range and high measurement accuracy, and can well meet the requirements of measuring the adhesion force between solid-liquid interface under electric field.

Fig. 1 shows a kind of measurement device of the utility model to measure the adhesion force between the solid-liquid interface under the electric field, comprising:

Transparent plastic operation cabinet 1;

A horizontal base 10, which is arranged in the transparent plastic operation cabinet 1;

Electric displacement platform 2, it is vertically arranged on the horizontal base 10;

A horizontal copper plate 8, which is arranged on a horizontal base 10; an electrowetting standard experimental sample 9 on a medium is adhered above the horizontal copper plate 8; wherein, droplets 7 are added dropwise on the electrowetting standard experimental sample 9 on the medium;

L-shaped cantilever beam 3, one end of which is connected to the sliding block of the electric displacement platform 2, and the other end is vertically facing the electrowetting standard experimental sample 9 on the medium, and the movement of the electric displacement platform 2 makes the vertical movement of the L-shaped cantilever beam 3 The straight end is in contact with the upper end of the droplet 7;

Laser sensor 14, it is vertically arranged on the electrowetting standard experimental sample 9 on the medium by the support frame and is aligned with the vertical end of the L-shaped cantilever beam 3 to photograph the displacement of the L-shaped cantilever beam 3;

A high-speed camera 11, which is arranged on a horizontal base 10, and said high-speed camera 11 is positioned on the side of the electrowetting standard experimental sample 9 on the medium to photograph the contact situation between the droplet 7 and the vertical end of the L-shaped cantilever beam 3;

The power supply 4 is arranged on the horizontal base 10, the positive pole of the power supply 4 is electrically connected to the L-shaped cantilever beam 3 through the wire I5, and the negative pole of the power supply 4 is electrically connected to the horizontal copper plate 8 through the wire II6; the power supply, the horizontal copper plate, the medium Electrowetting standard experimental samples and L-shaped cantilever beams are connected in series to form a circuit;

The data control processing terminal 18 is located outside the transparent plastic operation cabinet 1, and the data control processing terminal 18 is electrically connected with the electric displacement platform 2, the laser sensor 14, and the high-speed camera 15 respectively.

In this technical scheme, the bottom of the electrowetting standard test sample on the medium is bonded to the horizontal copper plate through conductive gel, and the horizontal copper plate is installed on the horizontal base; the horizontal copper plate, the standard test sample of electrowetting on the medium , The L-shaped cantilever beam is connected to the circuit; adjust the position of the laser sensor so that the beam is focused on the farthest end (vertical end) of the L-shaped cantilever beam; drip the liquid droplet to be tested on the surface of the electrowetting standard experiment sample on the medium, Make the end of the L-shaped cantilever beam contact with the droplet; turn on the power supply to set the voltage value; turn on the high-speed camera and laser sensor to record the experimental process; turn on the electric displacement platform to move at the set speed, so that the cantilever beam and the droplet to be tested will move relative to each other. A laser sensor records the deformation of the cantilever beam.

In the above technical scheme, the electrowetting standard test sample 9 on the medium is bonded above the horizontal copper plate 8 with conductive gel; the L-shaped cantilever beam 3 is an L-shaped pure copper tube with an outer diameter of 0.5mm , with an inner diameter of 0.25 mm; one end of the L-shaped cantilever beam is connected to the sliding block of the electric displacement platform through a conductive gel.

In the above technical scheme, as shown in Figure 2, the electrowetting standard experimental sample 9 on the medium comprises: a silicon wafer (conductive layer), an insulating layer plated on the silicon wafer and coated and dried on the insulating layer For the hydrophobic layer, silicon wafers are used as the conductive layer because silicon wafers are currently the most mature semiconductor conductive materials, which are the most cost-effective compared to other materials.

In the above technical solution, the insulating layer is a 200-400nm SiO ₂ coating, and the hydrophobic layer is a Teflon layer. The reason for choosing SiO ₂ coating is that SiO ₂ is now the most widely used insulating material, and it is currently the most cost-effective in terms of manufacturing technology and cost, and the smooth surface of SiO ₂ will not affect the coating of the hydrophobic layer, 200-400nm The choice of the thickness is because when the thickness is too small, although a large contact angle change can be obtained at a small voltage, it is easy to cause the breakdown of the hydrophobic layer; when the thickness is too large, if you want to get a larger contact angle Angle changes require a larger voltage; after consulting relevant data and experiments, it is found that 200-400nm is the best choice range under the existing experimental conditions.

Teflon is used as the hydrophobic layer because Teflon has the advantages of excellent chemical stability, low price, and corrosion resistance, and the coating method has lower requirements for the experimental environment than metal vapor deposition and plasma chemical vapor deposition. , low cost, and simple experimental operation.

In the above technical solution, as shown in Figure 3, the support frame includes a vertical support frame 12 and a horizontal support frame 13 with the same structure and vertically connected; the structure of the support frame includes:

The fixed end I19 and the fixed end II23 arranged in parallel are connected by two parallel linear guide rails 20;

Sliding block 22, which is slidably connected to two parallel linear guide rails 20;

The ball screw 21 is screwed and connected with the fixed end I19, the sliding block 22 and the fixed end II23 in sequence; by rotating the ball screw 21, the sliding block 22 can be driven to move on the linear guide rail;

Wherein, the fixed end I of the vertical support frame 12 is connected to the horizontal base 10, the fixed end I of the horizontal support frame 13 is connected to the sliding block of the vertical support frame 12; the laser sensor 14 is connected to On the slide block of horizontal support frame 13. In this way, the position of the laser sensor 14 can be adjusted conveniently and quickly through the vertical support frame 12 and the horizontal support frame 13 .

In the above technical solution, the electric displacement platform 2 is electrically connected to the data control processing terminal 18 through the displacement platform data output port 17; the laser sensor 14 is electrically connected to the data control processing terminal 18 through the laser data output port 16; The high-speed camera 11 is electrically connected to the data control and processing terminal through the image data output port 15. This method is mainly through the establishment of an integrated port mode, so that the data can be uniformly and synchronously output, so that a certain segment of data can be conveniently extracted in the future. and video analysis.

The method for measuring the adhesion force between the solid-liquid interface under the electric field by using the measuring device of the present utility model comprises the following steps:

Step 1. Use a pipette to add 10uL droplets to the surface of the electrowetting standard test sample on the medium;

Step 2. Turn on the laser sensor, adjust the position of the sliding block of the horizontal support frame, focus the laser beam on the vertical end of the L-shaped cantilever beam, and turn on the electric displacement platform, adjust the sliding block of the electric displacement platform to make the L-shaped cantilever beam The end of the vertical end is in contact with the upper end of the droplet; then the current position is set as the zero position of the laser sensor and the electric displacement platform;

Step 3: Turn on the power and set the voltage value to 100V; simultaneously turn on the laser sensor and high-speed camera to record the whole experiment process; turn on the electric displacement platform to move upward at a speed of 0.015mm/s, so that the L-shaped cantilever beam and the droplet to be tested will generate Relative movement, when the liquid droplet is completely separated from the surface of the electrowetting standard experiment sample on the medium, the movement of the electric displacement platform is stopped; the change of the displacement of the L-shaped cantilever recorded by the laser sensor with time during the entire experiment process is derived through the data control processing terminal Situation (as shown in Figures 4 and 5);

Step 4. Bring the outer diameter and inner diameter of the L-shaped cantilever beam into the following formula:

In the formula, D is the outer diameter of the L-shaped cantilever beam, which is 0.5mm, and d is the inner diameter of the L-shaped cantilever beam, which is 0.25mm. The calculated moment of inertia I=2.89×10 ^-15 m ⁴ ;

Step 5. Put the displacement change value of the L-shaped cantilever beam obtained in step 3 (as shown in Figure 5, the value obtained in the circle is the displacement change value) and the moment of inertia in step 4 into the following formula to calculate the adhesion force size:

In the formula, the elastic modulus of the L-shaped cantilever beam is E=101GPa, the horizontal length of the L-shaped cantilever beam is L=90mm, the moment of inertia I=2.89×10 ^-15 m ⁴ , and the displacement change of the L-shaped cantilever beam is ΔL=0.18mm. Force F = 231.6 μN.

In the above technical scheme, the preparation method of the electrowetting standard test sample on the medium is as follows: cutting the silicon wafer coated with SiO ₂ coating on the surface into a 30*30mm standard sample, and then ultrasonically cleaning the standard sample for 5 minutes, and using The absorbent paper absorbs the moisture on the surface, dries it, and keeps the surface clean; put the clean and clean sample on the desktop coating machine, and spin-coat Teflon emulsion; the spin coating parameters of the desktop coating machine are as follows: at a low speed of 500r/min Spin coating for 20s; spin coating at a high speed of 3000r/min for 30s; finally, place the spin-coated experimental sample in an oven at 200°C for 3 hours and let it cool naturally to obtain a standard experimental sample of electrowetting on the medium.

In the above technical solution, the preparation method of the L-shaped cantilever beam is as follows: take a pure copper tube with a length of 190 mm, an outer diameter of 0.5 mm, and an inner diameter of 0.25 mm, and bend it at 90° to form two parts of 100 mm and 90 mm Made into an L-shaped cantilever beam.

Although the embodiment of the present utility model has been disclosed as above, it is not limited to the use listed in the description and the implementation, and it can be applied to various fields suitable for the present utility model. For those familiar with the art, Further modifications can be readily effected, so the invention is not limited to the specific details and examples shown and described herein without departing from the general concept defined by the claims and their equivalents.

Claims (2)

1. A measuring device for measuring the adhesion force between the solid-liquid interface under the electric field, is characterized in that, comprising: Transparent plastic operation cabinet; A horizontal base, which is set in a transparent plastic operation cabinet; Electric displacement platform, which is vertically arranged on the horizontal base; A horizontal copper plate, which is arranged on a horizontal base; a standard electrowetting test sample on a medium is bonded to the top of the horizontal copper plate; wherein, droplets are added to the standard electrowetting test sample on the medium; L-shaped cantilever beam, one end of which is connected to the sliding block of the electric displacement platform, and the other end is vertically facing the electrowetting standard experimental sample on the medium, and the vertical end of the L-shaped cantilever beam is connected to the droplet through the movement of the electric displacement platform. the upper end contact; The laser sensor is vertically arranged directly above the electrowetting standard experimental sample on the medium through the support frame and aligned with the vertical end of the L-shaped cantilever to photograph the displacement of the L-shaped cantilever; A high-speed camera, which is arranged on a horizontal base, and the high-speed camera is positioned on the side of the electrowetting standard experimental sample on the medium to photograph the contact situation between the droplet and the vertical end of the L-shaped cantilever beam; The power supply is arranged on the horizontal base, the positive pole of the power supply is electrically connected to the L-shaped cantilever beam through the wire I, and the negative pole of the power supply is electrically connected to the horizontal copper plate through the wire II; A data control processing terminal, which is located outside the transparent plastic operation cabinet, and the data control processing terminal is electrically connected to the electric displacement platform, the laser sensor, and the high-speed camera respectively; The electrowetting standard experiment sample on the medium is bonded above the horizontal copper plate with conductive gel; the L-shaped cantilever beam is an L-shaped pure copper tube with an outer diameter of 0.5 mm and an inner diameter of 0.25 mm; One end of the type cantilever beam is connected to the sliding block of the electric displacement platform through conductive gel; The electrowetting standard experiment sample on the medium includes: a silicon wafer, an insulating layer plated on the silicon wafer, and a hydrophobic layer coated and dried on the insulating layer; The insulating layer is a 200-400nm _SiO2 coating, and the hydrophobic layer is a Teflon layer; The support frame includes a vertical support frame and a horizontal support frame that are identical in structure and vertically connected; the structure of the support frame includes: The fixed end I and the fixed end II arranged in parallel are connected by two parallel linear guide rails; a sliding block, which is slidably connected to two parallel linear guide rails; The ball screw is connected to the fixed end Ⅰ, the sliding block and the fixed end Ⅱ in turn by threads; Wherein, the fixed end I of the vertical support frame is connected to the horizontal base, and the fixed end I of the horizontal support frame is connected to the sliding block of the vertical support frame; the laser sensor is connected to the sliding block of the horizontal support frame. Move the block on. 2. the measuring device of adhesion between the solid-liquid interface under the measurement electric field as claimed in claim 1, is characterized in that, described electric displacement platform is connected with data control processing terminal electric communication by displacement platform data output port; The sensor is electrically connected to the data control processing terminal through the laser data output port; the high-speed camera is electrically connected to the data control processing terminal through the image data output port.