CN214794329U - Contact angle measuring device - Google Patents

Abstract

The utility model relates to a contact angle measurement field. The utility model discloses a contact angle measuring device, which comprises a light source, a container, photoelectric detector, the bubble produces unit and processing unit, the container is made by the printing opacity material, including relative first lateral wall and second lateral wall, the container is inside to be full of non-light tight liquid, the light source is monochromatic light source, the monochromatic light that the light source sent sees through first lateral wall and incides to the interface of first lateral wall and liquid with the total reflection angle or be greater than the total reflection angle, the bubble produces the unit and is used for producing one with first lateral wall internal surface contact's bubble, photoelectric detector's detection face is sealed wears to establish the second lateral wall and contacts with liquid, a light distribution condition for surveying monochromatic light sees through liquid, photoelectric detector's output termination processing unit. The utility model discloses realize the measurement of printing opacity liquid and printing opacity solid surface contact angle, can effectively solve the error that arouses through shooting image calculation and image pixel brought.

Description

Contact angle measuring device

Technical Field

The utility model belongs to the contact angle field of measuring specifically relates to a contact angle measuring device.

Background

The wettability of solid surfaces plays an important role in many fields such as artificial organs, biomaterials, etc. Contact angle is an important method for indirectly measuring the wettability of a solid surface.

The contact angle of a surface is mostly measured at present by analyzing the contact angle through a method of shooting images, such as the following patent publications: CN102507390A discloses a method for detecting a static contact angle during hydrophobicity, which comprises the steps of collecting a water droplet image, analyzing the water droplet image, selecting a designated algorithm for analysis on water droplets under different conditions, and finally obtaining a contact angle. The patent publication: CN102507391A provides a method for detecting the static contact angle of a water droplet in hydrophilic property, which comprises: acquiring a water drop image; selecting a circle fitting algorithm or an ellipse fitting algorithm to calculate an estimated value of the static contact angle of the water drop; and selecting a circle fitting algorithm or an ellipse fitting algorithm to calculate the accurate value of the static contact angle of the water drop according to the volume of the water drop and the estimated value of the static contact angle of the water drop.

Most of the existing contact angle measurement methods rely on image processing, and due to optical limitations, especially near a three-phase contact line, inherent errors exist, although the contact angle errors can be reduced by improving image resolution, the errors cannot be completely eliminated, and the measurement accuracy is influenced.

Disclosure of Invention

An object of the utility model is to provide a contact angle measuring device is used for solving the technical problem that above-mentioned exists.

In order to achieve the above object, the utility model adopts the following technical scheme: the utility model provides a contact angle measuring device, including the light source, the container, photoelectric detector, bubble generation unit and processing unit, the container is made by the printing opacity material, including relative first lateral wall and second lateral wall, the container is inside to be full of printing opacity liquid, the light source is monochromatic light source, monochromatic light that the light source sent sees through first lateral wall and incides to the interface of first lateral wall and liquid with the angle of total reflection or be greater than the angle of total reflection, bubble generation unit is used for producing a bubble with first lateral wall internal surface contact, photoelectric detector's detection face seals to wear to establish the second lateral wall and contact with liquid, a light intensity distribution condition for detecting monochromatic light and see through liquid, photoelectric detector's output termination processing unit.

Further, the container is of a square structure.

Further, the light source is an LED light source.

Further, the photoelectric detector is an area array CMOS photoelectric detector.

Further, the pressure control device is also included and is used for adjusting the internal pressure of the container.

Further, the bubble generation unit comprises a needle head and an air source, the air inlet end of the needle head is communicated with the air source, the needle head penetrates through the first side wall in a sealing mode, and the air outlet end of the needle head is located on the inner side of the first side wall.

Further, the processing unit is a computer.

Furthermore, the device also comprises a test bracket, and the light source and the container are fixed on the test bracket.

The utility model has the advantages of:

the utility model discloses can realize the measurement of printing opacity liquid and printing opacity solid surface contact angle, can effectively solve the error that causes and image pixel brought through shooting image calculation among the current measurement contact angle technique, measure the precision height.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a partial cross-sectional view of an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of an embodiment of the present invention;

fig. 3 is a schematic view of the contact angle of the present invention;

FIG. 4 is a schematic diagram illustrating the principle of measuring contact angle by evanescent waves according to the present invention;

fig. 5 is a simulation diagram of evanescent wave propagation for different contact angles according to the present invention.

Detailed Description

To further illustrate the embodiments, the present invention provides the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the embodiments. With these references, one of ordinary skill in the art will appreciate other possible embodiments and advantages of the present invention. Elements in the figures are not drawn to scale and like reference numerals are generally used to indicate like elements.

The present invention will now be further described with reference to the accompanying drawings and detailed description.

As shown in fig. 1 to 3, a contact angle measuring device comprises a light source 2, a container 1, a photodetector 7, a bubble generating unit and a processing unit 6, wherein the container 1 is made of a light-transmitting material and comprises a first side wall and a second side wall which are opposite to each other, in the embodiment, the container 1 has a square structure, the structure is simple, the measuring operation is easy, but the invention is not limited to this, and in other embodiments, the container 1 can also have other shapes such as a cylinder shape, a prism shape and the like.

In this embodiment, the first side wall and the second side wall are respectively a lower side wall 11 and an upper side wall 12 (with reference to fig. 1 as the direction), which is simple and convenient to operate, but the invention is not limited thereto, and in other embodiments, the first side wall and the second side wall may be respectively an upper side wall and a lower side wall, or left and right side walls, etc.

The container 1 is filled with a transparent liquid 3, the light source 2 is a monochromatic light source and is disposed outside the first sidewall 11 of the container 1, in this embodiment, the light source 2 is disposed below the lower sidewall 11 of the container 1, and monochromatic light 21 emitted by the light source 2 penetrates the lower sidewall 11 and enters the interface between the lower sidewall 11 and the liquid 3 at an angle of total reflection or greater. Of course, in other embodiments, the light source 2 may be embedded inside the lower sidewall 11, so as to make the structure more compact.

In this embodiment, the light source 2 is preferably an LED light source, which is easy to implement, low in cost, long in service life, and environment-friendly, but not limited thereto, and in other embodiments, the light source 2 may also be implemented by using other existing monochromatic light sources.

In this embodiment, the light source 2 is a surface light source, and the light spot area may cover the entire lower sidewall 11, or may cover a range extending outward by a certain distance with the bubble 4 as the center, thereby reducing the size of the light source 2 and reducing the cost.

The bubble generating unit is used for generating a bubble 4 contacting with the inner surface of the lower side wall 11, and the bubble 4 contacts with the inner surface of the lower side wall 11 irradiated by monochromatic light 21.

In this embodiment, the bubble generating unit includes a needle 5 and an air source (not shown in the figure), an air inlet end of the needle 5 is communicated with the air source, the needle 5 is hermetically inserted through the lower sidewall 11, and an air outlet end of the needle 5 is located at an inner side of the lower sidewall 11 and close to the lower sidewall 11, so that bubbles 4 generated at the air outlet end of the needle 5 are adsorbed on an inner surface of the lower sidewall 11. Of course, in other embodiments, the needle 5 may penetrate other side walls of the container 1, as long as the air outlet end is close to the lower side wall 11, so that the air bubbles 4 generated at the air outlet end of the needle 5 are adsorbed on the inner surface of the lower side wall 11. The gas source can be realized by a gas pump or a gas cylinder, which can be easily realized by the person skilled in the art and is not described in detail.

The detection surface 71 of the photodetector 7 is hermetically inserted through the upper sidewall 12 to contact with the liquid 3, and is used for detecting the light intensity distribution (including intensity and spatial distribution) of the monochromatic light 21 passing through the liquid 3, and the output end of the photodetector 7 is connected with the processing unit 6. The detection surface 71 of the photoelectric detector 7 is in contact with the liquid 3, so that the influence of secondary scattered light and secondary refracted light on a light intensity distribution area caused by the wall of the container 1 on the measurement accuracy can be avoided.

In this embodiment, the detecting surface 71 of the photodetector 7 is embedded in the inner surface of the upper sidewall 12 and is flush with the inner surface of the upper sidewall 12, so that the structure is more compact, and the photodetector 7 is easily disposed in a waterproof manner, but the invention is not limited thereto.

Preferably, in this embodiment, the photodetector 7 is an area array CMOS photodetector, which is easy to implement and low in cost, but is not limited thereto, and in other embodiments, an area array CCD photodetector or the like may be used.

In this embodiment, the processing unit 6 is a computer, but is not limited thereto, and in other embodiments, the processing unit 6 may be a mobile phone, an IPAD, or the like.

In this embodiment, the test device further comprises a test support 9, and the light source 2 and the container 1 are fixed on the test support 9, so that the test is facilitated.

Further, in this embodiment, the pressure controller 8 is further included, and the pressure controller 8 is configured to adjust the internal pressure of the container 1, so as to measure the contact angle θ under a constant pressure state, thereby improving the measurement accuracy, or the internal pressure of the container 1 may be changed in real time, so as to change the magnitude of the contact angle θ, thereby achieving measurement of the dynamic contact angle θ.

The pressure controller 8 may be any of various commercially available pressure controllers, which are well-established products and can be easily implemented by those skilled in the art, and will not be described in detail.

The measurement principle is as follows:

if no bubble 4 exists, the monochromatic light 21 enters the liquid 3 from the lower side wall 11 of the container 1 at the total reflection angle or greater, and is totally reflected at the interface between the lower side wall 11 and the liquid 3, so that the monochromatic light 21 cannot enter the liquid 3, and meanwhile, the monochromatic light 21 generates evanescent waves at the interface between the lower side wall 11 and the liquid 2 to propagate along the interface, and therefore, no monochromatic light 21 penetrates above the liquid 3. However, because the bubble 4 is located at the interface between the lower sidewall 11 and the liquid 4, the tension distribution at the edge of the bubble 4 microscopically affects the tension at the solid-liquid-gas three-state boundary, so that the material distribution near the three-phase contact line changes in wiener size, the refractive index at the solid-liquid intersection fluctuates, and when the monochromatic light 21 enters at a total reflection angle, a part of the light will transmit through the liquid 3 and generate a coherence phenomenon above the incident angle, as shown in fig. 4, so that the photodetector 7 can detect corresponding light intensity. Fig. 5 simulates the effect of different contact angles θ on monochromatic light 21: the light source is placed in the glass medium and obliquely enters water at an angle larger than the total reflection angle, and it can be seen that when the Contact Angle (CA) is changed, the electric field distribution above the bubbles is changed, and meanwhile, a coherent phenomenon occurs in the glass medium. Therefore, when the contact angle theta is different, the light intensity distribution conditions detected by the photoelectric detector 7 are also different, and the light intensity distribution conditions detected by the photoelectric detector 7 are transmitted to the computer 6 for processing, so that the contact angle theta can be obtained. For example, an influence curve of the contact angle theta on the light intensity can be calibrated in advance, and then the magnitude of the contact angle theta is reversely deduced through the influence curve, so that the wettability of the surface of the solid (container) or the tension of the liquid can be known.

When the surface wettability of different light-transmitting solid materials is to be measured, the different light-transmitting solid materials are made into the container 1, then the light intensity distribution condition is detected by the photoelectric detector 7, and the light intensity distribution condition is transmitted to the computer 6 for processing, so that the size of the contact angle theta can be obtained, and the surface wettability of the solid can be further known.

When the tension of different light-transmitting liquids is to be measured, the liquid to be measured is injected into the container 1, and then the light intensity distribution is detected by the photoelectric detector 7 and then transmitted to the computer 6 for processing, so that the size of the contact angle theta can be obtained, and the tension of the liquid can be known.

The utility model discloses can realize the measurement of printing opacity liquid and printing opacity solid surface contact angle, can effectively solve the error that causes and image pixel brought through shooting image calculation among the current measurement contact angle technique, measure the precision height.

While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (8)

1. A contact angle measuring device characterized by: the device comprises a light source, a container, a photoelectric detector, a bubble generation unit and a processing unit, wherein the container is made of a light-transmitting material and comprises a first side wall and a second side wall which are opposite, the container is internally filled with light-transmitting liquid, the light source is a monochromatic light source, monochromatic light emitted by the light source penetrates through the first side wall and enters an interface between the first side wall and the liquid at a total reflection angle or greater than the total reflection angle, the bubble generation unit is used for generating bubbles which are in contact with the inner surface of the first side wall, a detection surface of the photoelectric detector penetrates through the second side wall in a sealing mode and is in contact with the liquid and is used for detecting the light intensity distribution condition of the monochromatic light penetrating through the liquid, and the output end of the photoelectric detector is connected with the processing unit.

2. A contact angle measuring apparatus according to claim 1, characterized in that: the container is of a square structure.

3. A contact angle measuring apparatus according to claim 1, characterized in that: the light source is an LED light source.

4. A contact angle measuring apparatus according to claim 1, characterized in that: the photoelectric detector is an area array CMOS photoelectric detector.

5. A contact angle measuring apparatus according to claim 1, characterized in that: also included is a pressure controller for regulating the internal pressure of the vessel.

6. A contact angle measuring apparatus according to claim 1, characterized in that: the bubble generating unit comprises a needle head and an air source, the air inlet end of the needle head is communicated with the air source, the needle head penetrates through the first side wall in a sealing mode, and the air outlet end of the needle head is located on the inner side of the first side wall.

7. A contact angle measuring apparatus according to claim 1, characterized in that: the processing unit is a computer.

8. A contact angle measuring apparatus according to claim 1, characterized in that: the device also comprises a test bracket, and the light source and the container are fixed on the test bracket.

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