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Figure 3.19.

 Air-liquid surface tension measurement by pendant drop method. 

 

Figure 3.20.

 Liquid-liquid interfacial tension measurement by pendant drop method. 

 

 

Meniscus experiments

 

The fibers commonly used with Meniscus experiments are very thin, and so often requires the use of the 

zoom lens and additional lighting for the zoom lens. Before beginning the measurement, clean the solid 

appropriately and attach it to the syringe clamp.  

Theta instrument can be used to investigate cylindrical shapes such as rods or fibers as well as shapes 

that are not symmetrical about their axis such as plates. For the sake of convenience for the rest of this 

section of the manual the solid sample will be referred to as a rod, but keep in mind that plates, fibres, 

etc. can also be used. 

Adjust the position of the rod until it is visible on the image. Lift the liquid or lower the rod until the two 

surfaces intersect and a meniscus is formed. If necessary use a trigger, in most cases it should be 

sufficient to manually press Start/ Record once the meniscus is visible.  

 

 

Содержание Theta

Страница 1: ...Theta User manual OneAttension Optical Tensiometer Revision 1 0...

Страница 2: ...4 OPERATION OF ADDITIONAL MODULES 25 4 1 Automatic movement 25 A Vertical dispenser movement 25 B Automatic X sample stage 28 C Automatic XYZ sample stage 31 4 2 Automatic dispensers 32 A Automatic s...

Страница 3: ...6 3 Theory of surface free energy 65 7 TECHNICAL SPECIFICATIONS 70 8 CONTACT INFORMATION 71...

Страница 4: ...ostatted measuring chamber Tilting cradle High speed imaging Pulsating drop module The OneAttension software included with this instrument allows the easy operation of a variety of preprogrammed exper...

Страница 5: ...f Theta The figure below illustrates the hardware of Theta Figure 1 1 Theta physical features 1 Stage level adjustment 10 Manual dispenser adjustment 2 Stage height adjustment 11 Syringe clamp 3 Stage...

Страница 6: ...s A FireWire cable runs from the body of the instrument to the camera and another attaches Theta to a computer The FireWire card can be installed in any free slot on a computer The resolution used is...

Страница 7: ...gram Choose measurement method by clicking sessile drop pendant drop meniscus or pulsating drop icon Click Adjust Camera Parameters and choose automated camera adjustement by clicking Auto adjust You...

Страница 8: ...ent Image recording Fill in the relevant data in the recipe sheet It might be necessary to add users liquids or solids to the database manager found in the Setup tab With a surface tension measurement...

Страница 9: ...t angle values for the SFE analysis tab click Calculate The SFE results will appear on the lower part of the SFE analysis tab 3 General operation instructions 3 1 Software overview The OneAttension so...

Страница 10: ...the administrator Figure 3 5 Login with the created username and password in the OneAttension software The OneAttension software is a windows based program whose format will be easily learned by most...

Страница 11: ...king the Recipe Manager on the top right corner of the Instrument home tab The measurement window will then automatically appear with the pre defined values in the recipe Once a pre programmed experim...

Страница 12: ...ta produced based on new information about the materials involved You can also look at a variety of graphs for your data Calculation of additional results and export of data can be done You can also p...

Страница 13: ...ed into the recipe is created and edited If you are using additions which are not available from the current default menu you may enter into this section to add new choices to the database This sectio...

Страница 14: ...nge current user s settings Enable to select the path for each user where the measurements will be saved Change current user s password The User is able to change her his password Re login The other u...

Страница 15: ...alibration ball and its magnetic holder on the sample stage Bring the ball into the image on screen and zoom it appropriately by altering the lens zoom adjustment 15 The larger the drop on screen the...

Страница 16: ...e calibration tool There should now be a green line around the image of the calibration ball showing the curve that was fitted on it and screen showing the calibration factor Figure 3 13 Theta is now...

Страница 17: ...data obtained through Sessile drop experiments a further type of analysis Surface free energy is also available The procedures of the Sessile drop Pendant drop ad Meniscus experiments are very similar...

Страница 18: ...tings Start the experiment Choose the preferred experiment type by clicking the experiment icon After this automated devices will automatically initialize their locations Sessile drop experiment Penda...

Страница 19: ...the image Interfacial tension experiments the liquid inside a cuvette or another vessel completely fills the screen Meniscus experiments the liquid surface is visible and level Check the quality of t...

Страница 20: ...r experiment This also makes the recognition of the experiment easier later on when browsing experiments for further analysis Comment Additional comments can be added if necessary Autosave Software au...

Страница 21: ...nitial duration s In case Advanced Image recording mode is used the initial recording time is set here Software calculates automatically the initial duration after the total and final duration has bee...

Страница 22: ...utton will erase the previous live results from the Live result window Only record button will start recording according to Image recording parameters defined in the recipe sheet Real time operating f...

Страница 23: ...ispenser adjustment 10 is used to place the drop on the surface To place a drop on the sample lower one of appropriate size from the dispenser Simply press down on the Syringe height adjustment 8 and...

Страница 24: ...lso be done with one liquid within another if the two are immiscible Figure 3 20 This kind of interfacial tension measurement is done with a hooked needle with the denser liquid in a cuvette around it...

Страница 25: ...e clamp Theta instrument can be used to investigate cylindrical shapes such as rods or fibers as well as shapes that are not symmetrical about their axis such as plates For the sake of convenience for...

Страница 26: ...of the drop fills a larger part of the screen Whenever possible set the magnification so that the image of the drop is as large as possible Size of drops Ideal drop size varies with different applica...

Страница 27: ...e camera so that it is pointing slightly downwards towards the sample less than 5 The more distant surface of the sample is seen receding above the front of the sample In this case the reflection of t...

Страница 28: ...ly one additional hardware module is attached it must be connected to the AUX1 port only When two additional hardware modules are attached they must be connected to AUX1 and AUX2 ports only Attention...

Страница 29: ...orts in the automatic dispenser movement holder The first time after the experiment tab will be opened the stage will initialize itself by driving to the top end to properly establish its position Aft...

Страница 30: ...he surface Place drop Dispenses a drop and then executes a stroke Sets the home position which is defined by the user The dispenser holder needs to be set home before starting the experiment by pressi...

Страница 31: ...libration Check that the calibration is accurate before using the Stroke or Place drop functions B Automatic X sample stage The C320 Automatic X sample stage is used for automatic movement of the soli...

Страница 32: ...encer is used Points can be added by Add to list button by running the sample stage in the preferred position and then pressing the Add to list in the X stage control device Figure 4 6 Device controls...

Страница 33: ...e Sequencer generator window which enables to set N amount of measurements points with defined distance in X direction when automatic dispense holder dispenser and X sample stage are used Figure 4 7 S...

Страница 34: ...will initialize itself after which the stage will return to the zero position Attention Be sure that no measurement chambers or temperature modules are attached to the sample stage during homing to av...

Страница 35: ...e plastic syringe piston inside the Hamilton 1ml syringe Place the syringe in the groove and turn the plastic cover clockwise to the horizontal closed position Pull the piston of the syringe down to t...

Страница 36: ...r Drop Out or Drop In is pressed Volume from image Software is able to define the drop volume from the image due to calibration Figure 4 10 Device controls and adjustable recipe sheet parameters of th...

Страница 37: ...nd click Calibrate Fill the dispenser syringe with a liquid Weigh an empty container and dispense the contents of the syringe into it by pressing the Start button Allow the syringe to empty and weigh...

Страница 38: ...ed vertical movement If you are upgrading from a manual precision syringe loosen the thumbscrew on the vertical arm of the motorized dispenser movement lift the syringe holder assembly up from out of...

Страница 39: ...mp module to the mains The tubes from black couplings go to the liquid containers and the tubes from white couplings go to the needles This is important as the syringes will be emptied when Theta is t...

Страница 40: ...4 15 are the same than with the single liquid dispenser excluding the following addition functions Use Liquid 1 4 recipe sheet 1 4 buttons in the device controls Enabling corresponding channel transla...

Страница 41: ...38 Figure 4 15 Device controls and recipe sheet parameters for multiliquid dispenser...

Страница 42: ...rol unit The additional zoom optics is required to see the small drops that can be observed The additional light source enables observation at higher zooms The liquid vessel holds the liquid sample Th...

Страница 43: ...a drop Conducting a measurement and calibration Use a dry disposable syringe to press air into the liquid vessel to push the sample liquid into the dispenser head and a few drops out of it This is to...

Страница 44: ...coliter dispenser s device controls Figure 4 19 It might be necessary to adjust the focus by using test droplets Test droplets can be fired from the picodispenser device controls In the recipe sheet t...

Страница 45: ...x and a sample compartment surrounded by a ceramic insulator Plug in the serial cable to be connected between the control unit and the Theta Connect the serial cable to the port of the control unit an...

Страница 46: ...Operational 230 V 50 60 Hz 115 V 50 60 Hz The whole sample compartment consists of the following items Figure 4 21 An insulating ceramic base plate with the heating plate and a cable for connecting to...

Страница 47: ...amber so that the windows are visible and so that the needle fits through the hole at the top into the sample compartment For individual steps see pictures below from left to right Figure 4 22 Setting...

Страница 48: ...onscreen is similar to what would be seen with a standard contact angle experiment Plug in the serial cable to be connected between the tilting cradle and the Theta AUX X Note that the additional seri...

Страница 49: ...device controls Figure 4 25 In the recipe sheet speed of the movement can be adjusted In addition the target angle can be set from the device controls and initialization angle are visible here The fun...

Страница 50: ...e drop leaves the surface When the images are ready image analysis is the same as with a standard contact angle experiment see Chapter 5 except that the left contact angle will now show an advancing c...

Страница 51: ...mplitude 1 l Sample liquid volume needed 5 l Connections The pump chamber contains the piezo pump that oscillates the drop at the end of the needle A syringe is used as the liquid reservoir A Teflon t...

Страница 52: ...on started from the Oscdrop device controls Amplitude 1 1 Set a suitable amplitude Figure 4 27 Device controls of the PD 200 and the adjustable parameters in the recipe sheet Figure 4 28 Triple point...

Страница 53: ...e Oscdrop analysis as shown in Figure 4 30 The calculated results will then appear in lower left corner of the Analysis tab Figure 4 31 giving the following additional information of these surface int...

Страница 54: ...51 Figure 4 30 Analysis tab of the PD 200 experiment Figure 4 31 Calculated results...

Страница 55: ...igure 4 32 Graph of the analyzed surface tension and drop area as a function of time Figure 4 33 Graph Oscdrop results function to draw a graph of the oscillation results as a function of the frequenc...

Страница 56: ...d frequencies 4 6 Upgrading high speed camera 1550 fps If you have purchased high speed 1550 fps camera upgrade please contact your local Attension support representative or submit a support enquiry o...

Страница 57: ...een analyzed Analyze right away with default settings Figure 5 1 By clicking Yes the software will automatically curve fit and analyze the results according to the default settings shown in Drop Analy...

Страница 58: ...e also chosen for the analysis by clicking on a row which highlights the selected data point s In this case select the experiments which you prefer to analyze and then choose the preferred Data Analys...

Страница 59: ...ta according to chosen Data Analysis settings Mark as contact angle You can mark any data point or group of the data points to be used in surface free energy calculations Selected data point or averag...

Страница 60: ...d graph you are able to copy or export the statistic table or format the columns or numbers Hide selected rows Enable to hide the selected row s The hidden rows will not be included in the further ana...

Страница 61: ...e Analysis tab select the chosen angle by highlighting the row and then right clicking the Mark as contact angle Figure 5 5 Also group of the data points can be selected when the software calculates t...

Страница 62: ...ess Calculate and the results will appear in the lower part of the tab Figure 5 7 The available SFE models include Zisman OWRK Extended Fowkes Wu Acid Base Equation of State Simple Fowkes Schultz 1 an...

Страница 63: ...he receded contact angle These angles fall within a range with advanced angles forming a maximum value and receded angles forming a minimum value If the three phase boundary is in actual motion the an...

Страница 64: ...y water and similarly when receding in a hydrophilic region the contact angle decreases the solid tries to hold on to the water From this analysis it can be seen that with water advancing angles chara...

Страница 65: ...e surface tension It is most helpful in situations such as in multi component systems where the surface tension at the interface may not equal equilibrium surface tension Also referred to as the Adhes...

Страница 66: ...m These units are equivalent The surface is the interface of two fluids The experiment is referred to as a surface tension measurement if it involves a gaseous phase If two liquids are tested then th...

Страница 67: ...g gravitational constant R0 radius of drop curvature at apex The shape factor can be defined through the Young Laplace equation expressed through 3 dimensionless first order equations as shown in the...

Страница 68: ...uids of differing surface tensions a graph of cos vs is produced It will be found that the data form a line which approaches cos 1 at a given value of This value called the critical surface tension ca...

Страница 69: ...finding values for d s and p s such that the following square error function is minimized That is a generalized version of the Extended Fowkes method in which two drops are used to create a pair of eq...

Страница 70: ...Young s equation The equation of state can be formulated as follows where sl is the interfacial tension between the solid and the liquid Young s equation establishes a relation between the surface in...

Страница 71: ...first one and applying Young s equation cos WH SW SH we obtain SW H d W d S WH H W E 2 1 2 1 2 1 2 cos This can be solved by taking measurements with different hydrocarbons as submerging liquids and p...

Страница 72: ...69 References W A Zisman ACS Adv Chem Ser 43 1 1964 J Schultz K Tsutsumi and J B Donnet J Colloid Interface Sci 59 272 and 277 1977 D Li and A W Neumann J Colloid Interface Sci 148 1 pp 190 200 1991...

Страница 73: ...ee PCI slot Accessories Automatic dispensers and sample stages measuring chambers thermostated measuring chambers tilting cradle pulsing oscillating drop bubble module Experiments available Static con...

Страница 74: ...can be contacted from this address Attension Tiet j ntie 2 FI 02130 Espoo Finland Tel 358 0 9 5497 3300 Fax 358 0 9 5497 3333 E mail info attension com for sales requests support attension com for ser...

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