1、Designation: C813 90 (Reapproved 2014)Standard Test Method forHydrophobic Contamination on Glass by Contact AngleMeasurement1This standard is issued under the fixed designation C813; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、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 This test method covers the detection of hydrophobiccontamination on glass surfaces by means of contact an
3、glemeasurements. When properly conducted, the test will enabledetection of fractions of monomolecular layers of hydrophobicorganic contaminants. Very rough or porous surfaces maysignificantly decrease the sensitivity of the test.1.2 The values stated in SI units are to be regarded asstandard. No oth
4、er units of measurement are included in thisstandard.1.3 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 o
5、f regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent Water3. Terminology3.1 Definitions:3.1.1 advancing anglethe largest angle observable when aliquid droplet is increased in size.3.1.2 hydrophilichaving a strong affinity for water; wet-tab
6、le.3.1.2.1 DiscussionHydrophilic surfaces exhibit zero con-tact angles.3.1.3 hydrophobichaving little affinity for water; nonwet-table.3.1.3.1 DiscussionHydrophobic surfaces exhibit contactangles appreciably greater than zero: generally greater than 45for the advancing angle.3.1.4 receding anglethe
7、smallest angle observable when aliquid droplet is decreased in size.3.1.5 sessile dropa drop of liquid sitting on the upper sideof a horizontal surface.3.1.5.1 DiscussionSee Fig. 1.4. Summary of Test Method4.1 The contact angle test is performed by depositingdroplets of permanganate-distilled water
8、or reagent water inaccordance with Specification D1193 on the surface to betested using a mounted hypodermic syringe, said dropletsbeing deposited in such a way, as described herein, as tomeasure the advancing contact angle. The measurements shallbe made by either of these two well-known methods: (1
9、)viewing the sessile drop through a comparator microscopefitted with a goniometer scale with direct measurement of theangle; or (2) photographing the sessile drop and measuring theangle with a protractor. The interpretation of the measurementsis based on the fact that organic contamination on surfac
10、esresults in contact angles appreciably higher than the near-zeroangles measured on clean surfaces or those contaminated byhydrophilic materials.5. Significance and Use5.1 The contact angle test is nondestructive and may be usedfor control and evaluation of processes for the removal ofhydrophobic co
11、ntaminants. The test may also be used for thedetection and control of hydrophobic contaminants in process-ing ambients. For this application, a surface free of hydropho-bic films is exposed to the ambient conditions and is subse-quently tested.6. Interferences6.1 Loss of sensitivity may result from
12、either of the follow-ing factors:6.1.1 The presence of hydrophilic substances on the surfaceto be tested, or in the water used for the test, or6.1.2 An unusually rough or porous surface.1This test method is under the jurisdiction of ASTM Committee C14 on Glassand Glass Products and is the direct res
13、ponsibility of Subcommittee C14.02 onChemical Properties and Analysis.Current edition approved Oct. 1, 2014. Published October 2014. Originallyapproved in 1975. Last previous edition approved in 2009 as C813 90 (2009).DOI: 10.1520/C0813-90R14.2For referenced ASTM standards, visit the ASTM website, w
14、ww.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States17. A
15、pparatus7.1 Low-Power Comparator Microscope (5 to 50),withgoniometer scale and light source for illumination of smalldrops.7.2 Camera, that can take photographs of the drop if thisalternative method is used.7.3 Protractor, to measure the angle if the alternativemethod is used.7.4 Hypodermic Syringe
16、or Micrometer Buret, in a fixedmount. The needle of the syringe or the buret tip should be BDgage 20 to 26 or equivalent and should have a square-cut tip.7.5 Movable Platen, on which to mount the specimen whenviewing the drop in profile.8. Reagents and Materials8.1 Purity of WaterEither Type II reag
17、ent water in accor-dance with Specification D1193, or water distilled from a 3-g/Lpotassium permanganate solution is usually satisfactory. Thewater used must be free of hydrophobic and hydrophilicsubstances. To test the purity of the water for freedom fromhydrophobic contamination, a freshly cleaved
18、 sheet of micashall be used as the test surface for the measurement of theadvancing contact angle of the water as described in Section10. If the average of two such advancing contact angledeterminations is not less than 4, further purification of thewater is required.8.2 Mica.8.3 Polytetrafluoroethy
19、lene Sheet.9. Calibration and Standardization9.1 Contact angles of water on clean polytetrafluoroethyleneshall be measured to familiarize the operator with the test andserve as a check on the equipment and techniques. Advancingangles on polytetrafluoroethylene vary from 108 to 125,depending on the p
20、articular type of this high polymer used.10. Procedure10.1 Randomly select at least two sites where measurementswill be made on the test surface. Bring the syringe needle intoclose proximity to the test surface and, with the test surface ina horizontal position, manipulate the hypodermic syringe so
21、asto force a drop having a volume of 0.02 to 0.05 mL onto thesurface to give an advancing angle (Note 1). The needle shouldremain immersed in the drop and should be centered in thedrop. Care must be taken that when the syringe plunger isreleased no motion is imparted to the plunger so as to cause an
22、yretraction of the drop. Any retraction will cause the contactangle to be less than the true advancing angle (Note 2). Foreach site, measure two advancing angles by measuring thecontact angle on the left side and on the right side of the dropafter each of two successive incremental increases in the
23、dropsize (a total of four measurements for each drop for theadvancing angle). By making left- and right-sidedeterminations, the effect of a slightly nonlevel surface isalleviated. Where any consistent differences between the left-side and right-side determinations are noted, it is preferable tolevel
24、 the platen before proceeding (Note 3).NOTE 1Drops that are not deposited on a surface so as to exhibitadvancing or receding angles may have any value of the contact anglebetween this range of values.NOTE 2It is important that when making an advancing anglemeasurement, water be added to the drop unt
25、il the drop advances.NOTE 3Because of possible contamination by material present in theatmosphere, it is desirable to make the measurements promptly and toallow samples to sit unprotected no longer than necessary. Storage ofsamples in plastic containers or in containers with plastic or coated liners
26、should also be avoided. It is also very important to clean syringes andneedles carefully before making determinations on different specimens.Silicone grease is a common contaminant that must be avoided.11. Interpretation of Results11.1 Consider surfaces tested as described in Section 10 freeof hydro
27、phobic contaminants by this test if the advancing angleis no greater than 5. Under these conditions, organic contami-nation will be no greater than several percent of a monomo-lecular layer in coverage. It must be kept in mind that veryclean surfaces without oxide layers such as silicon and gold are
28、nonwettable by water and exhibit high contact angles.12. Precision and Bias12.1 Interlaboratory tests show that between-laboratoryvariations are about 610. Within-laboratory variations can beconsiderably less if the test is conducted with care.13. Keywords13.1 contact angle; contamination; glass; or
29、ganicFIG. 1 Schematic Diagram Indicating Measurement of ContactAngleC813 90 (2014)2ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the
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32、ave not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multip
33、le copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 90 (2014)3
