钉尖，引线框中接触角检测方案(接触角测量仪)

智能文字提取功能测试中

KRUSS Application Report Landing on the Point or Characterization of Microscopically Small Surfaces byMeans of Contact Angle Measurement Abstract Please have a brief look at a full stop mark in a newspaper text. Can you imagine dosing 20 to 30 drops on an area thissize and measure the contact angle? Or imagine the tip of a nail - even on this microscopically small area tiny little dropscan be dosed and measured. Such measurements are currently possible with the innovative micro-dosing system of thecontact angle measuring system DSA100M， which is able to dose precisely and on a point， very small drops down to a fewpicoliters. The following experiments show the potential of the new Micro-Dosing System DSA100M and may inspire you to newideas. Introduction On the 29th of December 1959， the physicist and laterholder of the Nobel prize， Richard Feynman gave alecture on： ，There’s Plenty of Room at the Bottom" at theannual general meeting of the American Physical Societyat the California Institute of Technology (Caltech). Hespoke about the possibility of manipulation and controlof things of a very tiny scale as well as about itstheoretical realization. Even at that time， people thoughtabout the miniaturization of systems. Since the late 1960s， much could be achieved in this fieldespecially in electronics. Electronic instruments such ascomputers today do not need a complete room for beinginstalled.Mobile phones or storage media like USB-sticksare meanwhile constructed in such a compact way thatthey fit into a trouser pocket. This progress among others wassmade possible because tthee measurinatechnique enabled us through the course of the years toadvance into smaller， miniaturized worlds. Today， kineticprocedures like the formation and rupture of chemicalbonds which take place within Femtoseconds (1015s) canbe observed [2]， or single molecules can be detected withinstrumental analysis [3-5]. The contact angle measuring technique these days alsocontributes to ，，miniaturization". The novel micro-dosingsystem， a new component to the modular measuringsystem DSA100， has been developed especially for verysmall sample surfaces. It is in the position to dose dropvolumes of only a few picoliters on a point. The followingperformancesshallilillustrateetthepotentialI(ofttheDSA100M by means of three chosen examples whichshall inspire you to new ideas. Experimental part Within the range of this work， the wetting behavior ofwater on different， microscopically small surfaces was tobe determined exemplarily by means of optical contactangle measurement by using the measuring systemDSA100M of KRUSS GmbH (see picture 1). Picture 1： Drop Shape Analysis System DSA100M of KRUSSGmbH The DSA100M is composed byfollowingmaincomponents： Basic instrument： Contact angle measuring systemDSA100 . Optics： 6 fold zoom lens with20x microscopeobjective， operating distance 20 mm， min. Field ofView 150 um Illumination ： High-Power LED Illumination ● Dosing modules： Piezo dosing for drops down topicoliters Detection： theavailable： optical systems ensureimage acquisition speed from 25 up to 1000 fps(fps = frames per second) The image acquisition speed of the following examplesalways was in the range of 250 frames per second，because the evaporation rate of extremely small drops isvery high. The standard test liquid used was water (Table 1). Liquid [mN/m] [mN/m] [mN/m] Water 72.80 21.80 51.00 Table 1： Data of test liquid water according to Strom [6] Results and Discussion Analysis of the wetting behavior of the dosinghead of an ink cartridge Using the Contact Angle Measuring System DSA100M， itis possible to analyze the surface of dosing heads of inkcartridges； with regard to their hydrophilicorhydrophobic properties. In general， the hydrophobicprint head surface should be more suitable for the use ofan ink cartridge than a hydrophilic surface， as water-based inks， due to weak interactions， produce discretedrops and more easily come off the dosing head. Picture 2： Water drops (Vol： approx. 100 pl) on the dosinghead of an ink cartridge. The image acquisition speed of thecamera was 250 fps. Picture 2 clearly shows the microscopically small area(approx. 80 um)， that is covered by the water drop on thedosing head. In this example， a water contact angle of@=66.2°was measured. Analysis of wetting behavior in capillary cavities Another possible application of the DSA100M ContactAngle Measuring System is the evaluation of the wettingbehavior of liquids in capillary cavities or depressions. Inpicture 3，，awater drop example isshownirin amicroscopically small sawn ，Canyon" with a width ofapprox.200 um and a depth of approx. 2 mm. The dropvolume in this case also was approx. 100 pl. With the DSA100M， we are now in a position to evaluatethe success or failure of surface treatment processes (e.g.plasma treatment) in capillary cavities Picture 3： Water drops (Vol： approx. 100 pl) in a sawn slotwith a width of approx. 200 um. The slot showed a depth ofapprox. 2 mm. Characterization of curved， fibrous material With the last case study， we will show that also thecharacterizationofcurved， fibroussurfaces ommicroscopic level is possible by means of the contactangle measuring technique. As an example， we compareda healthy， untreated hair with a hair that had beentreated with an oxidizing agent over several hours.Picture 4 shows a water drop of approx. 100 pl on asingle human hair with a diameter of approx. 150 pm. Picture 4： Water drop (Vol： approx. 100 pl) on human hair. Picture 5 shows the contact angles measured with theDSA100M on non-treated hair (above) and the hairtreated with oxidizing agent (below) depending on thetotal measuring period. non teatedhair Age sec Picture 5： Contact angle measuring data of five water dropsof approx. 100 pl applied at intervals of 5 s， on non-treatedhair (above) and of four water drops of approx. 100 pl onhair treated with oxidizing agent in dependency of the totalmeasuring period. The image acquisition speed of thecamera was 250 fps. The zigzag run of the gradient results from： a) Thee combinationi ot fast evaporation andpenetration of the liquid into the hair (sharp declineof the contact angle within 1-2 s). b) The repeated application of newliquid drops(abrupt rise of the contact angle data) To judge both hairs， you may consult the average valueof the contact angles measuredimmediately afterapplication of the water drops on the fiber (top of thepeak in both diagrams of picture 5， see red marks). Incase of the non-treated hair， we obtain a water contactangle of @=66.0°±4.5° and in case of the hair treatedwithh oxidizing agent， a waterr contact angle of@=82.3°±4.8°. The hair treated with oxidizing agentover a period of several hours thus shows a morehydrophobic behavior than non-treated hair. Summary Using the innovative Micro-Dosing Systems DSA100M，another component of the modular measuring systemDSA100， the ability to analyze the wetting behavior ondifferent microscopically small solid surfaces can betested. Therefore， contact angle measurements on waterdrops of approx. 100 pl were carried out. With three casestudies， we could show that it is not only possible tocharacterize plane surfaces but also three-dimensionalformed surfaces on a microscopic level with regard to thewetting behavior of liquids. Literature ( R. P. Feynman， Sci. E ng.23 (1960)， 20ff. ) ( A. H. Zewail， Angew. Chemie. 112 (2000)， 2689- ) 2738. ( [3] E. B. Shera， N. K. Seitzinger， L. M. Davis， R. A. ) ( Keller， S. A. Soper， Chem. P h ys. Lett. 174 (1990)， 55 3 -557. ) ( [4] B. Hecht， B. Sick， U . P . Wild， V. D eckert， R . Z e nobi， O.J. F . Martin， D. W. P ohl， J. Chem. Phys. 112 ( 2 000)， 7761-7774. ) ( [5] J. K . Gimzewski， C. Joachim， Science 283 (1999)， 1683-1688. ) ( [6] G.Strom， M . Frederiksson， P.Stenius； J. Coll. Int e rf. Sci.10， 119/2，352-361. ) KRUSS GmbH| Borsteler Chaussee Hamburg|Germany|www.kruss.de|