CN112129672A - Liquid contact angle measuring instrument by interference method - Google Patents
Liquid contact angle measuring instrument by interference method Download PDFInfo
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- CN112129672A CN112129672A CN202010941784.3A CN202010941784A CN112129672A CN 112129672 A CN112129672 A CN 112129672A CN 202010941784 A CN202010941784 A CN 202010941784A CN 112129672 A CN112129672 A CN 112129672A
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- liquid drop
- laser
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- 239000007788 liquid Substances 0.000 title claims abstract description 48
- 238000000034 method Methods 0.000 title claims abstract description 14
- 230000001427 coherent effect Effects 0.000 claims abstract description 6
- 239000007787 solid Substances 0.000 claims abstract description 5
- 238000005259 measurement Methods 0.000 claims description 9
- 230000000694 effects Effects 0.000 claims description 3
- 238000005305 interferometry Methods 0.000 claims 4
- 238000002474 experimental method Methods 0.000 abstract description 3
- 238000012545 processing Methods 0.000 abstract description 2
- 230000003287 optical effect Effects 0.000 abstract 1
- 239000003570 air Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000004556 laser interferometry Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N13/00—Investigating surface or boundary effects, e.g. wetting power; Investigating diffusion effects; Analysing materials by determining surface, boundary, or diffusion effects
- G01N13/02—Investigating surface tension of liquids
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N13/00—Investigating surface or boundary effects, e.g. wetting power; Investigating diffusion effects; Analysing materials by determining surface, boundary, or diffusion effects
- G01N13/02—Investigating surface tension of liquids
- G01N2013/0208—Investigating surface tension of liquids by measuring contact angle
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- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Length Measuring Devices By Optical Means (AREA)
Abstract
The invention discloses an interference method liquid contact angle measuring instrument which comprises a laser transmitter, an interference capturing module, an image interface, a supporting arm, a base, a leveling screw and a level gauge. When the leveling screw is adjusted to enable the level bubble to be located at the center, the laser can be vertically incident on the liquid drop through the generator. The light beam reflected by the contact surface of the air and the solid meets the coherence condition, the interference capturing module can identify the coherent formed fringes in the upper space of the liquid, converts the captured optical information into an electric signal and transmits the electric signal to an external computer through an image interface, and the interference fringes can be displayed on the external computer. And measuring the maximum transverse width of the interference fringes by using an interference equation to obtain the transverse width and the longitudinal width of the liquid drop, wherein the transverse width and the longitudinal width and the side length parameter of the liquid drop containing the contact angle. Finally the tangent function calculates the value of the contact angle of the drop. The liquid contact angle measuring instrument adopting the interference method has the advantages of accurate reading, easiness in operation, simplicity and convenience in data processing and improvement of experiment precision.
Description
Technical Field
The invention relates to a liquid contact angle measuring instrument by an interference method, in particular to a simple, convenient, visual, practical and accurate measuring instrument.
Background
In the current laboratory, there are two types of methods for measuring the contact angle of a liquid: the first is the differential circle method; another class is the laplace-poplar method. However, the errors of the two methods are large, the mathematical processing is very complicated, and the calculation of the contact angle with high precision requirements cannot be well met. The conventional method utilizes geometric approximation, and the contact angle range obtained by small estimation does not exceed 20 degrees, so that the method has great limitation.
Disclosure of Invention
In order to overcome the limitations of liquid contact angles, and the defects of large measurement error and small measurement range, the invention provides an instrument for measuring the liquid contact angle. By vertically emitting laser to the liquid drop, the laser is respectively reflected by the contact surfaces of the liquid drop, air and a solid, and because the two parts of reflected light come from the same light source and have the same vibration direction, the frequency and the phase difference are kept constant, and the coherence condition is further met, the light and dark stripes can be obtained. The relation between the distance between the stripes and the longitudinal height of the liquid drop is obtained through mathematical calculation, the transverse width of the liquid drop is obtained through observing the stripes, the contact angle of the liquid drop is obtained by applying a tangent function, and then accurate and convenient measurement is realized.
The technical scheme for solving the problem is that the liquid contact angle measuring instrument adopting the interference method comprises a laser transmitter, an interference capturing module, an image interface, a supporting arm, a base, a leveling screw and a level meter. The measuring instrument was placed on the laboratory bench and the level was adjusted so that the bubble was in the center position. The laser emitted by the laser is vertically incident on the liquid drop, the laser reflected twice by the liquid drop can generate a coherent effect in space according to the coherent condition, the effect is identified by the interference capturing module, and a data line led out through the image interface is connected to a computer to observe specific interference fringes. The relationship between the stripe distance and the longitudinal height of any point of the liquid drop is obtained through mathematical calculation, and the corresponding transverse width is obtained through observing the position distribution of the stripes. And finally, obtaining the contact angle of the liquid drop by using a tangent function, thereby realizing accurate and convenient measurement. The laser emitter, the interference capturing module and the image interface form a contact angle measuring loop.
In the interferometric liquid contact angle measuring instrument, the laser beam should be irradiated perpendicularly to the liquid droplet. The laser of vertical incidence has guaranteed that the interference light is coherent along same route, has also confirmed simultaneously that coherent light is caught by interference capture module completely, and then transmits the interference image for the computer.
The invention has the beneficial effects that: the liquid contact angle measuring instrument by the interference method can obtain relevant parameters related to the contact angle by performing mathematical analysis and solving on interference fringes of laser, and can obtain a specific numerical value of the liquid contact angle by applying a tangent function. Due to the adoption of laser interferometry, errors caused by reading are greatly reduced, calculation steps are reduced, the experiment precision is obviously improved, and the experiment flow is simplified.
Drawings
The invention is further explained below with reference to the figures and examples.
FIG. 1 is a design drawing of the present invention.
Fig. 2 is a schematic diagram of the present invention.
In the figure, 1, an interference light capturing module, 2, a laser emitter, 3, a supporting arm, 4, a level meter, 5, an image interface, 6, a leveling screw and 7, a base.
Detailed Description
[ example 1 ]
The interference method liquid contact angle measuring instrument comprises an interference light capturing module (1), a laser emitter (2), a supporting arm (3), a level gauge (4), an image interface (5) and a leveling screw (6). Firstly, a leveling screw (6) positioned at the lower end of the base is adjusted to enable the bubble of the level gauge (4) to be positioned at the center, and meanwhile, the laser can be vertically emitted to the liquid drop by the laser emitter (2).
[ example 2 ]
The laser beam is reflected by the contact surface of the liquid, air and solid, and the two beams of light meet the coherence condition, and the coherence fringe is identified by an interference capture module (1) positioned on the laser emitter (2). The interference capturing module (2) converts the captured fringe signal into an electric signal, and transmits the electric signal to display software on a computer through an image interface (5), so that a clear interference fringe image can be observed.
[ example 3 ]
After obtaining the interference fringe image, the longitudinal height of the liquid drop can be obtained by applying an interference equation to the fringe. The width of the interference fringes determines the longitudinal height of the liquid drop, and when the interference fringes captured by the interference light capturing module (1) are analyzed and measured, the maximum width of the two sides of the interference fringes is the transverse width of the liquid drop. Because the image interface (5) is directly connected with an external computer, data obtained by interference images in the computer correspond to the transverse and longitudinal lengths of real liquid drops, and the numerical measurement of the contact angle is realized.
Claims (5)
1. The liquid contact angle measuring instrument adopting the interference method comprises an interference light capturing module (1), a laser emitter (2), a supporting arm (3), a level gauge (4), an image interface (5), a leveling screw (6) and a base (7). And adjusting a leveling screw (6) at the lower end of the base (7) to enable the air bubble of the level meter (4) to be positioned at the center. The laser emitted by the laser emitter (2) is vertically incident on the liquid drop, the laser is respectively reflected by the contact surfaces of the liquid drop, air and a solid, and because the two parts of reflected light come from the same light source and have the same vibration direction and constant frequency and phase difference, the coherent condition is further met, and the light and dark stripes can be obtained. The interference effect is identified by the interference capturing module (1), and specific interference fringes can be observed by connecting a data line led out through the image interface (5) to a computer. The relation between the distance between the stripes and the longitudinal height of the liquid drop is obtained through mathematical calculation, the transverse width of the liquid drop is obtained through observing the stripes, the contact angle of the liquid drop is obtained by applying a tangent function, and then accurate and convenient measurement is realized.
2. The interferometry liquid contact angle measurement instrument according to claim 1, wherein: after the leveling screw (6) positioned at the lower end of the base (7) is adjusted, the air bubble of the level meter (4) can be positioned at the center, and the base (7) is adjusted to be in a horizontal state.
3. The interferometry liquid contact angle measuring instrument according to claim 1 or 2, wherein the laser emitted by the light emitter (2) is vertically incident on the liquid drop, the laser is respectively reflected by the contact surface of the liquid drop with air and a solid, and because the two parts of reflected light originate from the same light source, and the vibration directions are the same, the frequency and the phase difference are kept constant, and further the coherence condition is satisfied, the fringes with alternate light and dark can be obtained.
4. The interferometry liquid contact angle measurement instrument according to claim 3, wherein: the interference effect is identified by the interference capturing module (1), and specific interference fringes can be observed by connecting a data line led out through the image interface (5) to a computer.
5. The interferometry liquid contact angle measurement instrument according to claim 4, wherein: the relation between the distance between the stripes and the longitudinal height of the liquid drop is obtained through mathematical calculation, the transverse width of the liquid drop is obtained through observing the stripes, and the contact angle numerical value of the liquid drop is obtained by applying a tangent function.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010941784.3A CN112129672A (en) | 2020-09-09 | 2020-09-09 | Liquid contact angle measuring instrument by interference method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010941784.3A CN112129672A (en) | 2020-09-09 | 2020-09-09 | Liquid contact angle measuring instrument by interference method |
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| Publication Number | Publication Date |
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| CN112129672A true CN112129672A (en) | 2020-12-25 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010941784.3A Pending CN112129672A (en) | 2020-09-09 | 2020-09-09 | Liquid contact angle measuring instrument by interference method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113203662A (en) * | 2021-05-11 | 2021-08-03 | 厦门理工学院 | Contact angle measuring device |
-
2020
- 2020-09-09 CN CN202010941784.3A patent/CN112129672A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113203662A (en) * | 2021-05-11 | 2021-08-03 | 厦门理工学院 | Contact angle measuring device |
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| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20201225 |
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| WD01 | Invention patent application deemed withdrawn after publication |