DD147414A1 - Method and device for determining the surface accountability - Google Patents

Method and device for determining the surface accountability Download PDF

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Publication number
DD147414A1
DD147414A1 DD21718579A DD21718579A DD147414A1 DD 147414 A1 DD147414 A1 DD 147414A1 DD 21718579 A DD21718579 A DD 21718579A DD 21718579 A DD21718579 A DD 21718579A DD 147414 A1 DD147414 A1 DD 147414A1
Authority
DD
German Democratic Republic
Prior art keywords
liquid
wetting
wettability
slope
determining
Prior art date
Application number
DD21718579A
Other languages
German (de)
Other versions
DD147414B1 (en
Inventor
Roland Lipp
Ernst-Otto Reher
Ludwig Grader
Christine Hoffmann
Original Assignee
Roland Lipp
Reher Ernst Otto
Ludwig Grader
Christine Hoffmann
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Roland Lipp, Reher Ernst Otto, Ludwig Grader, Christine Hoffmann filed Critical Roland Lipp
Priority to DD21718579A priority Critical patent/DD147414B1/en
Publication of DD147414A1 publication Critical patent/DD147414A1/en
Publication of DD147414B1 publication Critical patent/DD147414B1/en

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Abstract

The invention "Method and Apparatus for Determining Surface Wettability" refers to the determination of the wetting properties of liquids on surfaces of interest in coatings and similar processes. The aim and the task consist in the simple, fast and accurate determination of the dynamic wettability of any plane surfaces in the range of technically interesting speeds. This is achieved by draining the liquid on a discharge ramp inclined to the horizontal, and by detecting the shape of the surface of the liquid running in the wetting area and its velocity. From the shape of the running liquid, the dynamic contact angle is determined. The device consists of a Ablaufschraege with light barriers and electronic Meszgeraeten, a movable Duese to the task of the liquid and a tempering. The invention can be applied in all areas of the art in which surface liquids are in contact, in particular in the coating of surfaces with fluids in film production.

Description

Int.Cl .: G 01 η 13/00
Method and device for determining surface wettability
Field of application of the invention
The invention relates to a method and a device for determining the wettability of a surface by a liquid. Determination of wetting properties of liquids on surfaces is required in coatings and other processes in which liquids and surfaces come into contact
Characteristic of the known technical solutions The determination of the wetting properties of liquids on surfaces is frequently carried out by measuring the equilibrium curvature of the liquid which forms on the surface.
The size of the weight-bearing edge angle is a measure of the wettability. DE OS 205 "3390 describes a method for determining the wettability of a surface, in which a multiplicity of liquid drops applied to the surface are illuminated and the angle of illumination is changed until reaching the critical angle of reflection to the observer,
 »!
With this method, the equilibrium edge angle at which the liquid is at rest can be determined with sufficient accuracy. "However, it is not possible to make a statement about the wetting properties when the liquid is in motion. It is known to the person skilled in the art that the dynamic wetting behavior of liquids on surfaces clearly differs from that in the stationary state. For the determination of the dynamic wetting behavior, a method is recommended according to DD-WP 117 528, in which a hanging meniscus of the liquid is generated on a rotating test cylinder. By this method, statements about the dynamic wetting behavior of the liquid on the test cylinder are possible. However, the method has a number of significant disadvantages. The test cylinder is wetted several times during the measurement. Thus, the wetting behavior of a liquid on an unwetted surface is not detectable. Furthermore, the production of cylinders having the surfaces to be examined is very complicated and not feasible in all cases. This greatly limits the examination of a wide variety of surfaces. It has also been found that the determination of the wetting speed from the peripheral speed of the rotating cylinder is not sufficient to characterize the dynamic wetting behavior of the liquid.
Another way to determine the dynamic wetting behavior is described by GRIBMOWA and MOLTSCHANOWA in Kolloidnui Zurnal 40 (1978) Kr. 1.30. It proposes to raise the liquid in cylindrical glass capillaries using micro-photography to determine the speed of wetting and the wetting angle. capture.
This method is suitable for measuring the dynamic contact angle at low and medium wetting speeds. However, it has the serious disadvantage that only the wetting of liquids on transparent capillaries can be investigated. This greatly limits the type of surfaces that can be used.
According to the method of ELLIOTT and RIDDIFORD (Journal of Colloid and Interface Sc. 23 (1967, 389), a drop of liquid between two flat plates is increased so that a constant wetting speed is achieved. "In this way the dynamic wetting behavior can be determined even on flat surfaces Despite the complicated and expensive liquid feed, the process can only achieve liquid velocities of less than 5.times.10.sup.-1 This low speed in no way meets the technical requirements.
E. WOLFRAM (Kolloid Zeitschrift 182 (1962) 1/2, 75) presents a method in which the angle of inclination of a drainage slope is determined at which a drop on it begins to roll off. The obtained value of the angle is, however, only an expression of the static wetting and the phenomenon designated by the person skilled in the art as edge angle hysteresis. With the method described by Y / OLFRAM it is not possible to obtain information on wetting with moving liquid.
Object of the invention
The object of the invention is to allow a simple, fast and accurate determination of the dynamic wettability of a surface, to avoid wetting disturbances and to make wetting processes more effective.
Explanation of the essence of the invention
The technical solutions known for determining the wettability of surfaces have the disadvantage that conclusions about the dynamic wettability of surfaces can not be drawn from a static drop. Other known technical solutions in which the dynamic wettability of surfaces can be determined are not suitable for Use any flat surfaces, as for the implementation of the method certain geometries such as capillaries are required and / or due to the geometries, low wetting speeds are feasible ο
The invention is therefore based on the object to develop a method and a device that allow determination of the dynamic wettability of any flat surfaces in the range of wetting speeds technically interesting.
According to the invention the object is achieved in that the liquid to a sloping to the horizontal drainage slope, the upper side of the surface to be examined
  5
is abandoned, so that it runs under the action of gravity, and that the shape of the surface of the effluent liquid in the wetting area and their speed are detected. The shape of the surface of the draining liquid in the wetting area can be photographically recorded. From the shape of the surface of the draining liquid in the wetting region, the dynamic contact angle is determined as a criterion for the wettability of a surface at the corresponding wetting speed. The liquid can be applied continuously in the form of a constant liquid flow to the drain slope,. , , A preferred device for carrying out the method according to the invention consists of a drainage slope whose
217185 - 5-
On the upper side has the surface to be examined, and which can be inclined at an arbitrary angle in the range of O ° ~ 9O ° relative to the horizontal, and a nozzle for the application of the liquid »
It is advantageous to attach a suitable scale to the drainage slope so that the angle of inclination of the drainage slope relative to the horizontal can be read directly. It is often necessary to examine the surface of a film. It is then appropriate to apply the film on the drainage slope. To get a good flatness, it can be sucked by vacuum. To maintain a certain temperature, it is advantageous to arrange a tempering chamber on the drainage slope or around the entire device.
At higher wetting velocities, the measurements of the velocity of the effluent liquid and the triggering of the optical device at the right time are difficult. It is therefore advantageous to attach two photocells so at the From sloping that they are successively interrupted by the draining liquid, measured by a suitable electronics, the time difference and the speed of the liquid flowing out and also with a certain delay, the optical device is triggered.
Embodiment 1
The invention will be explained in more detail below using an exemplary embodiment.
Fig. 1 shows an embodiment of the device according to the invention.
The device consists of a base plate 1 to which a stand 2 is attached.
A drainage slope 3 is connected to the stator 2 via a bearing 4. From the running slope 3 is rotatably mounted and its inclination angle, which can be between 0 ° and 90 ° leaves
- 6 -
read off at scale 5. About the nozzle 6, the liquid to be examined can be abandoned from a reservoir 7 to the drainage slope 3. The nozzle 6 can be arbitrarily set in its inclination angle to the drainage slope 3. On the drainage slope 3 is a film 8 of the surface to be examined.
An optical device 9 is arranged such that with it the shape of the liquid surface in the wetting region can be detected. The device is preferably suitable for determining the surface wettability of films. «

Claims (2)

    invention claim
  1. A method for determining the surface wettability of a liquid on a sloping down to the horizontal slope, ge η η ζ i ei ch η et dad urch that is allowed to flow the liquid on the inclined slope to the horizontal, the shape of the surface of the effluent liquid in the wetting area and their speed detected on the inclined slope and that determines the dynamic contact angle from the shape of the surface of the running 'liquid.
  2. 2 Apparatus for determining the surface wettability consisting of a drainage slope, ge η η ζ eich et η et by the fact that at the opposite to the horizontal in the angles in the range of O bx3 90 ° adjustably mounted downslope two photocells, the with electronic »tronic Measuring devices are coupled, located that above the drainage slope, a movable nozzle for preferably continuous task of the liquid is arranged and that there is a temperature control chamber on the drainage slope or the entire device.
    For this purpose 1 ropes drawings
    • v
DD21718579A 1979-11-28 1979-11-28 Method and device for determining the surface accountability DD147414B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DD21718579A DD147414B1 (en) 1979-11-28 1979-11-28 Method and device for determining the surface accountability

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DD21718579A DD147414B1 (en) 1979-11-28 1979-11-28 Method and device for determining the surface accountability

Publications (2)

Publication Number Publication Date
DD147414A1 true DD147414A1 (en) 1981-04-01
DD147414B1 DD147414B1 (en) 1988-07-27

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Family Applications (1)

Application Number Title Priority Date Filing Date
DD21718579A DD147414B1 (en) 1979-11-28 1979-11-28 Method and device for determining the surface accountability

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4970893A (en) * 1990-02-27 1990-11-20 Reid Philip L Tilt angle tester
FR2721399A1 (en) * 1994-06-17 1995-12-22 Kodak Pathe Photographic film substrate dynamic wetting limits determn. method
CN106018184A (en) * 2016-05-20 2016-10-12 大连理工大学 Experimental device for measuring dynamic contact angle under high-temperature and high-pressure environments

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4970893A (en) * 1990-02-27 1990-11-20 Reid Philip L Tilt angle tester
FR2721399A1 (en) * 1994-06-17 1995-12-22 Kodak Pathe Photographic film substrate dynamic wetting limits determn. method
CN106018184A (en) * 2016-05-20 2016-10-12 大连理工大学 Experimental device for measuring dynamic contact angle under high-temperature and high-pressure environments
CN106018184B (en) * 2016-05-20 2018-08-21 大连理工大学 The experimental provision of dynamic contact angle is measured under a kind of high temperature and high pressure environment

Also Published As

Publication number Publication date
DD147414B1 (en) 1988-07-27

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