CN102914490A - Solid-liquid contact angle measuring method in non-transparent or sealed space - Google Patents

Abstract

The invention relates to a method for measuring a liquid contact angle in non-transparent or sealed space. An optical imaging method in the prior art is replaced by the nuclear magnetic resonance imaging technology; through directly collecting a magnetic resonance signal of a liquid with nuclear spin quantum number of 1/2 of atomic nucleus number, a liquid section passing through an axis of a gas-liquid interface is imaged; and then through fitting an axis section curve of an image and through further measurement or calculation, a solid-liquid contact angle is obtained. As nuclear magnetic resonance imaging has no requirement on optical transparency of a research system, the defect that the traditional solid-liquid contact angle measuring method based on optical imaging only can measure solid-liquid contact angles in transparent and open space is eliminated. The method for measuring the liquid contact angle in the non-transparent or sealed space, provided by the invention, is especially suitable for researches on solid/liquid interface phenomenon in non-transparent environments or sealed systems.

Description

CN 102914490 A

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The method of solid-liquid contact angle measurement in an opaque enclosure or

[0001] TECHNICAL FIELD

The present invention relates to the field of measuring technology, particularly relates to a solid-liquid contact angle measuring method to characterize the material wettability. [0002] BACKGROUND

Invasive nature of the solid surface is important, has important applications in ore flotation, architectural coatings, waterproofing, etc., anti-corrosion. Because of its important role in scientific research and practical applications, solid surface wettability of research has been a hot field of physical chemistry content. Wherein the contact angle measurements as part of invasive basic research has important value for surface / interface theoretical research and production practice of science.

[0003] With the development of research and technological advances, we have been developed a variety of methods of measuring the contact angle, such as by Wilhelmy plate method, the hanging drop method, the bubble trap method and the like. Since the advantages of simple operation, the hanging drop method in the application contact angle measurements are most widely used, its main principle is to give micro-droplets on a solid surface shape image by optical imaging, by contour droplet fit analysis finally obtained The contact angle values. At present, most of the contact angle measurement are based on this principle.

[0004] However, since this method is based on optical imaging as the basic conditions, which will require that a contact angle measurements must be carried out in a transparent and open system. In practical applications, various wetting behavior often occurs in the case of an opaque or closed, e.g., noxious liquid surface tension of the liquid transport line fluid control, microfluidic systems, etc., which are invasive important application direction of research, but the system itself is opaque and closed, the traditional means of contact angle measurements can not be applied to such research, which has created a significant obstacle to the development of theory and practical application of surface and interface science.

[0005] For example, polytetrafluoroethylene and polyamides are commonly used in liquid conduit transport material, the wet state conduit for liquid transport and fluid parameters have an important impact efficiency. Thus, to obtain the contact angle of the fluid in the pipe, and fluid state for a further understanding of the important role in the regulation of fluid. However, since the opacity of the material, using methods conventional optical state of wetting liquid in the pipeline no way of knowing.

[0006] Thus the need of a new technology, research to achieve an opaque liquid wettability and a closed system.

[0007] [DISCLOSURE]

The present invention is to solve the technical problem: to develop a method capable of measuring opaque or enclosed space inside the solid-liquid contact angle.

[0008] The present invention provides a method for measuring blocking opaque or solid-liquid contact angle of the internal system, wherein the solid consists of non-ferromagnetic material, a liquid containing a nuclear spin quantum number of nuclei is equal to 1/2, the solid configuration filled with the liquid and air in the space, the method comprising:

SI placing the sample chamber to said solid-liquid system is magnetic resonance imaging device;

Pre-S2 system imaging the solid-liquid sample from at least one direction, image contrast analysis and to determine the liquid-gas interface position, direction and the center point of the liquid-air interface;

S3 from at least one direction, in a direction perpendicular to the liquid-gas interface of the plane through the center of the liquid-gas interface of said solid-liquid system liquid sample MRI, contrast and image analysis, to give sectional view of the liquid through the liquid-air interface of the central axis;

S4 according to the cross-sectional view, axial sectional curves to obtain a solid-liquid and liquid-gas interface;

S5 fitting the axial cross-sectional profile, and by measurement or calculation, the solid-liquid contact angle.

3 [0009] The solid may be any non-ferromagnetic material, such as glass, polytetrafluoroethylene, polyamide, or other non-ferromagnetic material.

[0010] Alternatively liquid from an aqueous liquid, an oily liquid or an oil mixture of water. Wherein the aqueous liquid may be water, or an aqueous solution, liquid or soluble in water, including alcohols and the like. The oily liquid may be an alkane, an aromatic hydrocarbon, esters, fatty acids and other organic compounds; refers to a liquid mixture of water and oil and water formed by mixing various organic compounds, compared to if the two immiscible solutions, if an emulsion is formed or immiscible layered form.

[0011] The opaque space may be closed or open space, and the space may be of any shape such as tubular, conical

Sit inch O

Step [0012] This process S5, the polynomial fit to the circle or ellipse fitting the fitting or the like.

[0013] protractor method can be measured or calculated or amount of the solid-liquid contact angle for the Supreme Court.

[0014] fit to the measured or calculated process may be carried out by measuring the contact angle and fitting software.

[0015] The fitting and conventional contact angle measurement software Drop Shape Analysis System (Kriiss, Germany)> Surftens (SURFTENS Universal, Germany)> SCA20 (Dataphysics, Germany) and the like.

[0016] Advantageous effects of the present invention is that: compared with the contact angle measurement based on optical imaging, the present invention is the use of magnetic resonance imaging as a means of using unique internal nuclear magnetic resonance imaging function can measure not only the conventional transparent or open space the solid in the system - liquid contact angle, can also be measured in an opaque or solid enclosed space system - liquid contact angle. To broaden the range of applications, more in line with the actual environment of the liquid wettability characterization.

[0017] BRIEF DESCRIPTION

Figure I is a flow chart solid-liquid contact angle measuring method according to the present invention.

[0018] FIG. 2 shows a comparison of the optical imaging and MRI imaging of the opaque space.

[0019] FIG. 3 is a method of the present invention, FIG opaque spatial imaging of different shapes.

[0020] FIG. 4 is a schematic view of the contact angle is measured using a circular fitting.

[0021] DETAILED DESCRIPTION OF THE INVENTION

Magnetic resonance imaging (MRI) technology is electromagnetic wave emitted by hydrogen nuclear detecting gradient magnetic field is applied to give a technical structure of the interior of the object image. Magnetic resonance is a physical phenomenon by Block and Purcell was first reported in 1946 and applied spectroscopy. After the early 1970s, PC Lauterbur and P. Mansfield breakthrough in the field of MRI, laid the foundation for the successful application of MRI.

[0022] In recent years, magnetic resonance imaging technology developed rapidly, has matured perfect. Because of its good all areas of destructive and non-invasive, magnetic resonance imaging technology has been widely applied to medical diagnosis, oil exploration, material characterization, and the like.

[0023] From the point of view imaging principle, it is imaged by magnetic resonance imaging of hydrogen nuclei directly acquired magnetic resonance signals, the optical transparency of the research system without any requirements, making it ideal for closed systems and the solid opaque environment / liquid study interfacial phenomena.

[0024] The inventors to investigate wettability PTFE tube and water tube for example polyamide, characterized wettability opaque under the conditions set forth principles. In the present invention, we can by means of magnetic resonance imaging in the imaging conditions advantage opaque, the opaque imaging successfully polytetrafluoroethylene and polyamide line liquids, and measured by analyzing the image of the boundary curve, thereby obtaining a contact angle values ​​obtained by the optical method is difficult.

[0025] conjunction with the accompanying drawings and the following specific embodiments of the present invention is described in further detail.

As shown in a flowchart [0026] I FIG solid-liquid contact angle measuring method according to the present invention. Seen from the figure, the measuring process includes the following five steps: first step of the SI, the discharge chamber to the sample in the magnetic resonance imaging system of a solid-liquid sample, and morphology solid interface shape may be any shape and morphology, experimental The samples were before without special treatment. Since the contact angle is calculated taking the angle between the gas-liquid interface and the solid-liquid interface by an amount to achieve, therefore, no matter how complicated the shape of the interface, as long as the liquid can accurately obtain the shape of the curve and the solid-liquid interface, can be fitted through The contact angle values ​​calculated.

[0027] In step S2, the pre-image of a solid-liquid system, the liquid sample from at least one direction, image contrast analysis and to determine the position of the liquid-air interface, and the direction of the central liquid-air interface. For accurate measurement, it is necessary to obtain the axial cross-sectional profile of a solid-liquid and gas-liquid interface.

[0028] When the spatial shape and surface morphology rules, transparent space or a space, the liquid is determined relatively easy axial sectional curve more, it can be judged by eye, and to set the imaging parameters directly from the spatial shape. So that the liquid can be imaged from only one direction, the imaging process is relatively simple, only a desired image can be obtained.

[0029] However, when the space is opaque, since the internal space of unknown status, would need to be pre-imaged, and the image contrast analysis, to determine the position of the liquid-air interface, and the direction of the central liquid-air interface. There may be imaged from multiple directions, the right to get accurate results.

[0030] Then, at step S3, it has been determined due to the liquid-gas interface position, direction and the center of the liquid air interface, then you can adjust the parameters of the magnetic resonance imager, from at least one direction, perpendicular to and through the liquid-air interface liquid-air interface of the center point of the plane (i.e., in a plane through the central axis of the liquid), a solid-liquid system, the liquid sample is magnetic resonance imaging, contrast and image analysis, to give a liquid through the central axis for further analysis the cross-sectional view.

After [0031] In step S4, according to a cross-sectional view taken, accurate axial cross-sectional profile of a solid-liquid and liquid-gas interface.

[0032] Finally, in step S5, the axial cross-sectional curve fitting, and by measurement or calculation, the solid-liquid contact angle.

[0033] The following specific examples, the inventors glass NMR tube, PTFE tube and water tube polyamide, wettability studies dodecane example, describes a solid-liquid solid-liquid contact angle measurement system, i.e., liquid wettability characterized principle.

[0034] Apparatus and Materials

Suzhou Niumai using Electronic Technology Co. bandit 120-Analyst magnetic resonance imaging for imaging a liquid analyzer.

[0035] The contact angle measurement software SCA20 (Dataphysics, Germany) magnetic resonance curve for the solid-liquid interface in the image fit.

[0036] Solid: PTFE tube (Φ12, a length of about 3. 5 cm); polyamide tube (Φ 12, a length of about 3. 5 cm); NMR glass tube (phi] 5 and Φ15).

[0037] Liquid: Secondary deionized water; dodecane.

[0038] Example I

Preparing a solid-liquid system: successively using acetone, ethanol, and washed with deionized water secondary Teflon tube sonicated for 15 minutes, drying standby; secondary Teflon tube of deionized water were calculated in accordance with the diameter injection of water, control of water column height such that the inner tube is not greater than 2 cm.

[0039] Control of the liquid level in order to meet the equipment used for this test sample height requirements should be appreciated that when using other solid-liquid systems, the space of different shapes, or other measurements on magnetic resonance imaging device, this parameter can be suitably adjustment, without affecting the scope of the present invention.

[0040] Magnetic Resonance Imaging: water - Teflon tubing system of vertically placed magnetic resonance imaging device, the selected z-axis

5 is an imaging or X-axis direction, the magnetic field strength is O. 5 T, a multi-layer spin-echo sequence is an imaging sequence, repeated sampling wait time 1000 ms, the accumulated number of times 32, the water tube polytetrafluoroethylene imaging .

[0041] Liquid axial sectional curve: adjusting image brightness and contrast, to obtain water from the drawing - and polytetrafluoroethylene air - aqueous phase interface curve.

[0042] Fitting and measuring and calculating: water contact angle measurement software SCA20 (Dataphysics, Germany) - and polytetrafluoroethylene air - aqueous phase interface fit, and the contact angle was measured to give the water contact with the duct angle of 107. 5 ± I. 1 °.

[0043] Example 2

Except that in place of the polyamide PTFE tube outside tube, similar to the procedure of Example I.

[0044] by a contact angle measurement software SCA20 (Dataphysics, Germany) water - for fitting aqueous phase interface, and the contact angle was measured to obtain the contact angle of water within the duct 69. 4 ± 1.9 ° - Polyamide and air .

[0045] Example 3

Except that instead of the secondary dodecane than deionized water, similar to the procedure of Example I. Wherein the magnetic resonance imaging procedure is repeated using the waiting time is 500 ms ο

[0046] by a contact angle measurement software SCA20 (Dataphysics, Germany) for twelve burn - dodecane phase interface for fitting, and the contact angle was measured to obtain the contact within the duct dodecane - PTFE and air angle of 45. 7 ± 2.0. .

[0047] Example 4

Except that instead of the secondary dodecane than deionized water, similar to the procedure of Example 2. Wherein the magnetic resonance imaging procedure is repeated using the waiting time is 500 ms ο

[0048] by a contact angle measurement software SCA20 (Dataphysics, Germany) for twelve burn - dodecane phase interface for fitting, and the contact angle was measured to obtain the contact angle of the dodecane duct - Air polyamide and 41. 3+ 3. 6 °.

[0049] Example 5

Except that instead of the PTFE tube Φ5 NMR tube except that steps similar to Example I.

[0050] The water contact angle measurement software SCA20 (Dataphysics, Germany) - _ glass and air interface to fit the aqueous phase, and the contact angle was measured to obtain the contact angle of water within the duct 24. 3 ± 2.7 °.

[0051] Example 6

Except that instead of the secondary dodecane than deionized water, similar to the procedure of Example 5. Wherein the magnetic resonance imaging procedure is repeated using the waiting time is 500 ms ο

[0052] by a contact angle measurement software SCA20 (Dataphysics, Germany) for twelve burning - glass and air - for fitting dodecane phase interface, and the contact angle was measured to obtain the contact angle of the dodecane to the duct 24 . 5 ± 2.8. .

[0053] Example 7

Except that instead of Φ15 NMR tube outside Φ5 NMR tube, similar to the procedure of Example 5.

[0054] The water contact angle measurement software SCA20 (Dataphysics, Germany) - _ glass and air interface to fit the aqueous phase, and the contact angle was measured to obtain the contact angle of water within the duct 29. I ± 5.6 °.

[0055] Example 8

Except that instead of the secondary dodecane than deionized water, similar to the procedure of Example 7.

6 [0056] by a contact angle measurement software SCA20 (Dataphysics, Germany) for twelve burn - dodecane phase interface for fitting, and the contact angle was measured to obtain the contact angle of the dodecane duct - glass and air 33. 7+ 6. 3 ° ο [0057] Examples 1-4 for solid-liquid contact angle was measured under conditions opaque; Example 5-8 for solid-liquid contact angle was measured under the conditions of transparency. The measuring method of the contact angle can be seen on magnetic resonance imaging of the present invention without any requirements for transparent solid, greatly broadens the coverage of the liquid wettability.

[0058] To illustrate, compared with the conventional methods based on optical imaging, the method of the present invention is based on the advantages of solid-liquid contact angle measurements of magnetic resonance imaging, the present invention is polytetrafluoroethylene tube water respectively and the optical imaging magnetic resonance imaging. The resulting images are shown in Figure 2, wherein a) an image of an optical imaging; b) of the MRI images.

[0059] As is evident from the figure, since the PTFE tube opaque, conventional optical method is difficult to understand the behavior of water wet Teflon tube, while clearly observed in the water may be by magnetic resonance imaging infiltration state Teflon tube. Thus the method of the present invention can be effectively overcome the optical imaging method in the opaque space can not image defects, particularly suitable for solid-liquid contact angle measurement space opaque, thereby helping to understand the wettability of a liquid on a solid opaque space.

[0060] Figure 3 is a nuclear magnetic resonance imaging, for Φ5 cylindrical glass NMR tube (A), and a conical glass container (b) water is imaged, the image obtained.

[0061] The method of the present invention can be seen there is no limitation on the shape of the space, which may be cylindrical, conical, or any other shape. FIG clearly reflects the image of the hydrophilic properties of the glass.

[0062] FIG 4 illustrates a schematic view of a circular fitting by using a contact angle β is measured.

[0063] above, we can by means of magnetic resonance imaging in the imaging conditions advantages opaque, opaque successfully achieved polytetrafluoroethylene and polyamide pipe, and an imaging fluid within the transparent glass NMR tube, and by boundary curve image analysis measurements, thereby obtaining the contact angle values ​​obtained by the optical method is difficult. Thus, the method of the present invention is transparent to the space, whether the space requirements no regular shape, greatly expand the solid-liquid contact angle measurement, and the scope of application of liquid wettability characterized.

[0064] DETAILED DESCRIPTION embodiment of the present invention described above, do not limit the scope of the present invention. Any of various technical concept of the present invention to make corresponding changes and other modification, should be included within the scope of the claims of the invention.

Claims (8)

1. CLAIMS 1. A method for measuring the space opaque or solid-liquid contact angle closure, wherein the solid consists of non-ferromagnetic material, a liquid containing a nuclear spin quantum number of nuclei is equal to 1/2, the space filled with the liquid and air, said method comprising: Si solid-liquid system, the sample is placed into the sample chamber of the magnetic resonance imager; S2 from a direction of said solid-liquid system, the liquid sample is subjected to at least pre-image, and the image contrast analysis, the liquid air interface in order to determine the position, direction and the center of the liquid-gas interface; S3 from at least one direction, perpendicular to the liquid-gas interface and the plane through the center of the liquid-gas interface of said solid-liquid system, the liquid sample nuclear magnetic resonance imaging, contrast and image analysis, to give a cross-sectional view of the liquid through the liquid-gas interface of the central axis; S4 according to the cross-sectional view, axial sectional curves to obtain a solid-liquid and liquid-gas interface; the axial S5 sectional curve fitting, and by measurement or calculation, the solid-liquid contact angle.
2. 2. The method according to claim I, wherein the solid selected from glass, polytetrafluoroethylene, a polyamide material.
3. 3. The method of claim I, wherein said liquid is selected from aqueous liquid, an oily liquid or a mixture of water and oil.
4. 4. The method of claim I, wherein the opaque space is closed or open space.
5. The method according to claim I, wherein the shape of said space comprises a tubular, cone.
6. 6. The method of claim I, wherein, in step S5, the fit to a polynomial fit, or circle fitting ellipse fitting.
7. 7. The method of claim I, wherein, in step S5, the measurement or calculation method using protractor or amount of solid-liquid contact angle for the Supreme Court.
8. 8. The method of claim I, wherein the fitting step S5 using the contact angle and measurement software.