1、Designation: D1331 14Standard Test Methods forSurface and Interfacial Tension of Solutions of Paints,Solvents, Solutions of Surface-Active Agents, and RelatedMaterials1This standard is issued under the fixed designation D1331; the number immediately following the designation indicates the year ofori
2、ginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover the determination of surfacetension a
3、nd interfacial tension of a variety of liquid materials,including but not restricted to paints, solvents, and solutions ofsurface-active agents, as defined in Terminology D459. Fourmethods are covered as follows:Method ASurface Tension by du Noy ring.Method BInterfacial Tension by du Noy ring.Method
4、 CSurface Tension by Wilhelmy plate.Method DInterfacial Tension by Wilhelmy plate.1.2 Method A originally was written primarily to coveraqueous solutions of surface-active agents, but is also appli-cable to aqueous paints, nonaqueous solutions (includingpaints) and mixed solvent solutions.1.3 Method
5、 B is applicable to two-phase solutions. Morethan one solute component may be present, including solutecomponents that are not in themselves surface-active.1.4 Method C is applicable to surface active liquids and,unlike du Noy ring, no buoyancy corrections are needed andresults are not affected by m
6、oderate viscosities (1-10 Pa-sec) ofthe liquid. It is the recommended method for use with paintsand resin solutions.1.5 Method D is applicable to two-phase solutions andmixtures.1.6 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandar
7、d.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Material Saf
8、etyData Sheets are available for reagents and materials. Reviewthem for hazards prior to usage.2. Referenced Documents2.1 ASTM Standards:2D459 Terminology Relating to Soaps and Other Detergents3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 du Noy ringplatinum wire ring.3.1.2
9、Wilhelmy plateflat, thin plate made of glass orplatinum.4. Summary of Test Methods4.1 du Noy Ring MethodsThe ring is suspended from atensiometer or balance. The test liquid is brought into contactwith the ring until the latter is covered. For interfacial tensionmeasurements, the ring must be at the
10、interface between thetwo liquids. The ring is then slowly withdrawn until amaximum force is attained, from which the surface or interfa-cial tension may be calculated.4.2 Wilhelmy Plate MethodsThe plate is suspended from atensiometer or balance. The test liquid or interface between twoliquids is bro
11、ught into contact with the bottom of the plate,causing the plate to be pulled down into the liquid by thesurface tension force. The force applied to the plate from aboveis then increased to bring the bottom edge of the plate levelwith the flat surface of the liquid. The force acting on the plateis m
12、easured and used to calculate the surface tension of theliquid or the interfacial tension between two liquid phases.5. Significance and Use5.1 These methods provide data that are useful in evaluatingthe effectiveness of surface active agents in reducing surface1These test methods are under the juris
13、diction of ASTM Committee D01 onPaint and Related Coatings, Materials, and Applications and are the directresponsibility of Subcommittee D01.24 on Physical Properties of Liquid Paints r, the radius, incentimetres, of the wire from which the ring is made; and V, themaximum volume of liquid elevated a
14、bove the free surface ofthe liquid. For liquids of low surface tension, such as surface-active agents, F is, in general, appreciably less than unity. Itmust, therefore, be ascertained and applied. Values of F interms of two compounded parameters, R3/V and R/r have beenD1331 142compiled and tabulated
15、 by Harkins and Jordan.3In order tolook up F in the tables, the values of these two parameters mustbe calculated. Values for R and r are furnished by themanufacturer with each ring. The value of V is calculated fromthe following equation:V 5 M/D 2 d! (1)where:M = weight of liquid raised above the fr
16、ee surface of theliquid,D = density of liquid, andd = density of air saturated with vapor of the liquid.To calculate M, multiply the tensiometer dial reading by thefactor which converts this reading into grams pull on the ring.The factor D can be measured by the usual procedures, and thevalue d can
17、be obtained from published data. The correctedsurface tension in dynes per centimetre is obtained by multi-plying the uncorrected surface tension value by F.11.2 Unless specified, the surface tension values reportedshall be corrected values. Report also the temperature at whichthe measurement was ma
18、de. If it is desired to report the surfacetension value of an aqueous solution at some standardtemperature, for example, 25C, and the measurement wasactually made at a temperature within about 3C of this value(that is, 22 to 28C), a correction factor of 0.14 dynes/cmCmay be used. Subtract this corre
19、ction factor from the surfacetension when the temperature of the test is lower than thereported temperature, and add it to the surface tension when thetemperature of the test is higher than the reported temperature.This value for the correction factor is not valid for nonaqueousliquids, and should b
20、e used only where the solvent is prepon-derantly water.METHOD BINTERFACIAL TENSION BY DU NOYRING12. Procedure12.1 Determine interfacial tension as described in Section10 for surface tension, with the following modifications:12.1.1 Always move the ring from the aqueous side of theinterface through to
21、 the nonaqueous side. With liquids lighterthan water, it is accordingly possible to use the precisiontensiometer as well as the interfacial tensiometer. With liquidsheavier than water, where the ring must be pushed downward,the interfacial tensiometer should be used.12.1.2 Use fresh solutions and a
22、freshly cleaned ring foreach determination.12.1.3 When operating with a liquid heavier than theaqueous solution, place the two-layer system in the samplevessel and place the ring in the upper (aqueous) layer. Make themeasurement by turning the torsion wire counter-clockwiseand simultaneously keeping
23、 the ring system in the zeroposition, as in the measurement of surface tension, until thering breaks through the interface.12.1.4 When operating with a liquid (oil) lighter than theaqueous solution, first place the aqueous solution in the samplevessel and immerse the ring therein. Carefully pour the
24、 oil ontop of the aqueous solution to form the two-layer system.Contact between the oil and the ring should be avoided duringthis operation. After allowing sufficient time for the interfacialtension to come to its equilibrium value (Note 3), make themeasurement in the same manner as that used for me
25、asuringsurface tension.NOTE 3Since the interfacial energy of a newly formed liquid-liquidinterface generally requires some time to reach its equilibrium value, it isadvisable to wait at least 5 min after the interface is formed before takinga measurement.13. Calculation and Report13.1 As in the case
26、 of surface tension, a correction factor, F,must be multiplied by the dial reading (pull on the ring indynes) in order to obtain the corrected value for interfacialtension. Values for F have been published by Zuidema andWaters.4The factor F is, in this case, a function of the densitiesof the two liq
27、uids as well as of R and r, the radius of the ringand that of the wire, respectively.13.2 Unless specified, interfacial tension values reportedshall be corrected values. Report and adequately specify thenature of the nonaqueous liquid (oil) used in the determination.Also report the temperature at wh
28、ich the determination wasmade. In contrast to surface tension values, interfacial tensionvalues cannot adequately be corrected for small temperaturedeviations by means of a simple formula.METHOD CSURFACE TENSION BY WILHELMYPLATE14. Apparatus14.1 Balance or Tensiometer with provision for attaching aW
29、ilhelmy plate.14.2 Thin Platinum or Glass Plate (microscope slides andcover slips have been used) with a means of connecting it to thebalance or tensiometer.15. Preparation of Apparatus15.1 Clean all glassware thoroughly. The use of freshchromic-sulfuric acid cleaning mixture, followed by a thor-oug
30、h rinsing in distilled water, is recommended.15.2 Clean platinum or glass plate by rinsing thoroughly ina suitable solvent and distilled water.15.3 For a correct surface tension the surface of the platemust be roughened and with no bright spots on the plate.16. Procedure16.1 After the tensiometer or
31、 balance has been calibrated,check the level and insert the cleaned platinum or glass plate3Harkins, W. D., and Jordan, H. F., “A Method for Determination of Surface andInterfacial Tension from the Maximum Pull on a Ring,” Journal Am. Chemical Soc.,Vol 52, 1930, p. 1751. These tables are also publis
32、hed in Physical Methods ofOrganic Chemistry, Interscience Publishers, Inc., New York, NY, Vol 1, 1945, pp.182184.4Zuidema, H. H., and Waters, G. W., “A Ring Method for Determination ofInterfacial Tension,” Industrial and Engineering Chemistry, Analytical Edition, Vol13, 1941, p. 312.D1331 143that wi
33、ll be used in the measurement. Extreme care must betaken to have the sample vessel and platinum or glass plateclean. Contamination of the liquid surface by dust or otheratmospheric impurities during measurement should beavoided.16.2 Check that the lower edge of the plate is exactly planeby ensuring
34、the light gap between the edge of the plate and thesurface is uniform.16.3 Place the liquid to be tested, contained in the thor-oughly cleaned vessel (16.1), on the sample platform. Forsurface active agents: since the surface tension of a solution isa function of the concentration, care must be take
35、n that theconcentration is adjusted and recorded within known limits.The presence of solutes other than the surface-active agentshould be ascertained and reported qualitatively andquantitatively, insofar as possible. This includes hardnesscomponents in the water. Care should be taken that the soluti
36、onis physically homogeneous. Measurements made near or abovethe cloud point or other critical solubility points can be inserious error. This is particularly true when the solute is asurface-active material.16.4 Rinse the platform to just below the plate. Tare theforce measuring system to zero.16.5 R
37、inse the sample platform until the plate is justsubmerged and turn the mechanical drag pointer to set it at thereference mark.16.6 Raise platform around another 5 mm to ensure thewetting of the plate and then lower platform until the dragpointer is pointing exactly to the reference mark again.16.7 R
38、ecord the force reading from the dial or the digitaldisplay.16.8 Make at least two measurements. Additional measure-ments shall be made if indicated by the overall variationobtained, the total number of readings to be determined by themagnitude of that variation.17. Calculation17.1 The surface tensi
39、on, , is computed from the forcemeasurement, f, using: 5 f$2 1 1 t!#% cos where:l = length of platet = thicknessThe contact angle is often assumed to be zero for commonliquids on clean glass or platinum plates, but one should beaware of the error caused by a non-zero contact angle. No othercorrectio
40、n factors are necessary for this method and the fluiddensity does not need to be known.METHOD DINTERFACIAL TENSION BYWILHELMY PLATE18. Procedure18.1 Determine interfacial tension as described in the pro-cedure for surface tension (Section 16), with the followingmodifications:18.1.1 Always remove the
41、 plate from the aqueous side ofthe interface through to the nonaqueous side. With liquidslighter than water, it is accordingly possible to use the precisiontensiometer as well as the interfacial tensiometer. With liquidsheavier than water, where the plate must be pushed downward,the interfacial tens
42、iometer should be used.18.1.2 Use fresh solutions and a freshly cleaned plate foreach determination.18.1.3 When operating with a liquid heavier than theaqueous solution, place the two-layer system in the samplevessel and place the plate in the upper (aqueous) layer. Makethe measurement by turning th
43、e torsion wire counter-clockwiseand simultaneously keeping the plate system in the zeroposition, as in the measurement of the surface tension.18.1.4 When operating with a liquid (oil) lighter than theaqueous solution, first place the aqueous solution in the samplevessel and immerse the plate therein
44、. Carefully pour the oil ontop of the aqueous solution to form the two-layer system.Contact between the oil and the plate should be avoided duringthis operation. After allowing the sufficient time for theinterfacial tension to come to its equilibrium value (Note 4),make the measurement in the same m
45、anner as that used formeasuring surface tension.NOTE 4Since the interfacial energy of a newly formed liquid-liquidinterface generally requires some time to reach its equilibrium value, it isadvisable to wait at least 5 min after the interface is formed before takinga measurement.19. Calculations and
46、 Report19.1 Calculate surface tension as is 17.1.19.2 Report and adequately specify the nature of the non-aqueous liquid (oil) used in the determination. Also report thetemperature at which the determination was made. In contrastto surface tension values, interfacial tension values cannotadequately
47、be corrected for small temperature deviations bymeans of a simple formula.20. Keywords20.1 du Noy ring; interfacial tension; surface tension;tensiometer; Wilhelmy plateD1331 144ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item ment
48、ionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee
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