User`s Manual - The Molecular Materials Research Center
Contents
1. J Instruments User s Manual Surface Potential Meter Revision 1 0 WWW KSVItd com x Instruments 1 INTRODUCTION 2 TECHNICAL SPECIFICATIONS 3 GENERAL INTRODUCTION 4 KSV SPOT PRINCIPLE OF MEASUREMENT 5 INSTALLING THE KSV SPOT 5 1 Installation steps 5 1 1 KSV SPOT software 5 1 2 Connecting cables 5 1 3 Using KSV SPOT with third party devices 5 1 4 Calibration of the KSV SPOT 6 MEASUREMENTS 6 1 Stand alone KSV SPOT 6 2 KSV SPOT connected to a KSV trough 7 EXAMPLE MEASUREMENTS KSV SPOT Manual KSV SPOT 12 12 15 18 Rev 1 0 Instruments KSV SPOT 1 Introduction KSV SPOT is a small computer controlled stand alone surface potential measuring instrument It is based on the non contact and non destructive vibrating plate capacitor method KSV SPOT has a high accuracy minimal drift and high reproducibility which guarantee a high sensitivity and stability for the measurements KSV SPOT is mainly designed for monolayer measurements but due to its stand alone property it is also suitable for surface potential measurements over a range of solids and liquids KSV SPOT enables you to complement surface pressure area data with the more sensitive surface potential data Thus giving you for example the following additional information about your monolayers e Composition e Dissociation degree e Orientation e Interaction e Adsorption The software included with this instr2. KSV SPOT Make sure that all parts needed to install KSV SPOT have been received Use the checklist below KSV SPOT measuring head Counter electrode made of stainless steel Stand for SPOT Cable for connecting the measuring head and counter electrode crocodile clip RCA cable 15 pin device cable for connecting SPOT measuring head to LayerBuilder unit e CD ROM disk for installing the SpotMonitor software and User s Manual in pdf format 5 1 Installation steps The KSV SPOT measuring head is controlled by a Window 2000 XP Vista compatible software 5 1 1 KSV SPOT software The SpotMonitor software is supplied on a CD ROM disk Load the software onto the desired drive using normal Windows procedures NOTICE This software needs to be installed only if the KSV SPOT is intended to be used as a stand alone unit If the KSV SPOT is intended to be used in combination with KSV s monolayer troughs the software for controlling the KSV SPOT will be integrated in the LB software In this case there is no need to install KSV SPOT Monitor software Measurement procedures will be described in section 6 2 5 1 2 Connecting cables The KSV SPOT measuring head is connected to the LayerBuilder Unit with 15 pin cable and to the counter electrode with a crocodile clip RCA cable The image below shows where the 15 pin cable and the crocodile clip RCA cable should be connected KSV SPOT Manual Rev 1 0 Instruments KSV SPOT 15
3. Make sure that reading in Second value native units has stabilized and press Next button After this the calibration is done and new calibration factor 1s stored into SPOT memory KSV SPOT Manual 11 Rev 1 0 Instruments KSV SPOT 6 Measurements 6 1 Stand alone KSV SPOT The measurements are performed with the SpotMonitor software Place the counter electrode beneath the measuring probe Adjust the height of the measuring head so that the gap between the test surface and the vibrating plate is a few mm Start the measuring head by switching the toggle switch to up position The complete system should be powered on at least one hour before starting an experiment and the Spot head should be turned on at least 10 minutes before starting an experiment Start switch for Spot head To start an experiment enter the Data Monitoring software by choosing Experiments Data Monitoring Software or press the Data Monitoring icon the Main Menu window The window for this section should appear as follows KS Data Monitoring Software File Edit view Controls Help B1 mg B2 mg Bri mm Br2 mm D1 mm D2 mm T C pH SPN Status Ready for new Experiment When using SpotMonitor software first time choose Edit in the Data Monitoring window The Instrument Parameters window will appear 12 KSV SPOT Manual Rev 1 0 Instruments KSV SPOT Balancel Probe Name T Perimeter 33 240 mm Balanc
4. This can induce variations in the results due to static disturbances from the barrier material If the surface potential values have to be shown on the screen during the real time experiment select SP V as the other y axis from the drop down menu in the Graph just after you have started your experiment ESY LB Control Software File Edit View Controls Help B1 mN m B2 rom Bri mm Brr mm 01 mm D2 mm T C Sample Interval 2 i al Status Waiting For Stark rr Idle frre None D1 None 16 KSV SPOT Manual Rev 1 0 Instruments KSV SPOT Trough1 Controls xX Trough1 Isotherm Data E E O x Compression Method Constant rate Compression Anis Mma AF 11 Asis SF mN m x 2A Nore i Mima nrt Recording Options Surface pressure versus Mean sP mN m rea 2 a aug aoe Soe in hg a rot rn fom oO to top Ip SP i E 9 renibotae ae of S EE Target Options f Surface Pressure f Mean Molecular amp rea Trough Area Barrier Position No of Cycles I al Gain Control BEE Target mN m 80 0 2 Rate mm min fio Compression Parameters After Target Parameters Mas Rate Fwd mm min J 50 44 Mas Rate Buyd mm min 504 Fause ZeroBal stop Go Go Hold ZeroPos IritB arrier Compress Expand 1 00 0 75 0 50 0 25 0 00 O25 O50 0 5 1 00 Mma 47 However even 1f the surface potential values are not shown on the screen duri
5. pin connector for device cable RCA connector for Counter Electrode ea Now the KSV SPOTI should be properly installed and ready for measurements 8 KSV SPOT Manual Rev 1 0 Instruments KSV SPOT 5 1 3 Using KSV SPOT with third party devices KSV SPOT has also an analog output for third party devices with analog input Analog output is from 5V to 5 V The KSV SPOT requires 12Vdc operating voltage Connection diagram is shown below C S input 12Vdc Pa otal input GND O 2 D O a on output QO 25 6 p m O 7 amp output GND 5 1 4 Calibration of the KSV SPOT NOTICE The KSV SPOT is factory calibrated and there should be no need for re calibrating it Below is described the calibration procedure in case calibration is needed Connect a DC power supply between Counter Electrode and the RCA connector on SPOT front panel The positive voltage should be connected to Counter Electrode and ground to RCA connector The voltage should be between 2 0 3 5Vdc Start SpotMonitor or KSV WinLB software KSV SPOT Manual Rev 1 0 Instruments KSV SPOT PV ralisnre in Cirtara Choarmietr Excellence in Surface Chemistry To calibrate the devices enter the System Diagnostics and Calibration software by choosing Experiments System Diagnostics and Calibration or press the System Diagnostics and Calibration icon XI the Main Menu window The window for this section s
6. points as a function of time can be started Insert the required values and press the Start button in the Measurement Controls window to begin the collection of data points The measurement is stopped automatically after the time inserted in the Measurement Control window The measurement can also be stopped before the measurement time has finished by pressing Stop in the Measurement Control window After the measurements have been done all facilities for data point presentations in the KSV SpotMonitor software graph print and export of the data points etc can be used for the collected surface potential data A new experiment is simply started by choosing New experiment from the File drop down menu in the Data Monitoring window 14 KSV SPOT Manual Rev 1 0 Instruments KSV SPOT 6 2 KSV SPOT connected to a KSV trough When measuring with KSV SPOT in combination with a KSV LB trough one can use any of the available experiments in the KSV WinLB software However a few preparative procedures have to be performed before the surface potential can simultaneously be collected with other measuring parameters KS LB Control Software File Edit view Controls Help Data Base D2 mm TEC pH Bra mm D1 mm B1 mtn B2 mN m Erri mm EJ Device Parameters aa a Sample Interval z il Status Select a new Experiment rr Idle frre None Di None Start the KSV WinLB and from the KSV LB Control Software wi
7. Coll Interf Sci 1988 126 408 i Phillips M C Cadenhead D A Good R J King H F J Coll Interf Sci 1971 37 437 Christie P Jones C A Petty M C Roberts G G J Phys D 1986 19 L167 5 KSV SPOT Manual Rev 1 0 Instruments KSV SPOT 4 KSV SPOT principle of measurement The block diagram of the measuring circuit of KSV SPOT meter is shown below Compensation Voltage Drive in Position Indicator electronics Control 3 3 wr Current Due to Capacitance Change T plate l Counter electrode The upper electrode vibrating plate of the capacitor is set to vibrate with a frequency between 100 180 Hz The upper electrode of the capacitor is placed a couple of mm from the test surface solid or air liquid interface depending on which type of measurement is performed As the upper electrode vibrates the capacitance between the electrode and the test surface changes This change in capacitance induces an AC current to the circuit due to the fact that there exists a potential difference between the electrode and the test surface This current 1s amplified and analyzed by together with the signal from the oscillator Thereafter the control electronics adjusts the DC current controlling the potential of the feedback capacitor until the compensating voltage equals the surface potential and no currents occur KSV SPOT Manual Rev 1 0 Instruments KSV SPOT 5 Installing the
8. es Probe Name gt Perimeter 33 240 nari Surface potential meter Sound card Spm connected OF Cancel Make sure that Sound card Spm connected box is unchecked and press OK button A new experiment is started by choosing New Experiment from the File drop down menu in the Data Monitoring window The Experimental Setup window will now appear Fill in the Experimental Setup form and press the Start button The User Sample and Additions information can be inserted in advance by editing the database Experimental Setup i x Mame Expt User JES Date 10 7 2008 08 53 55 Probe for Balance Frobe tor Balance Ferim lt 39 240 mm Ferim lt 39 240 mm Sample Hame Density 0 lade e 0 mim baa viscosity 0 mPas 12 ERE pH Comments Start Cancel Edit Data Base After pressing the Start button in the Experimental Setup window a Measurement Control window will appear 13 KSV SPOT Manual Rev 1 0 Instruments KSV SPOT Sample Interval z mz ua Rec On Meas Time min Recon M AutoSave Probe Controls Before Start Spd mm min m After Start Spd mm min C AutoStart Up C AutoStart Down f fone Lp Stop Dawn ero Position L ZeroBali ZercBal2 PEI Stop Start Hereafter the potential value can be zeroed by pressing ZeroSpm from the Measurement Control window and the collection of data
9. hould appear as follows saSystem Diagnostics j BE ioj xi Bile Tools Help o Name id Status Version pasi 5120 Display 128 80H 0 0H 3 0 o Display 129 851H OCOH 3 0 o o 0 Balanced 144 90H OfOH 31 1 0649e 09 Pho 152 98H O OH 33 1e 06 Somo 590FH O 0H 33 S 7686e 07 0 Calibrate Scroll the Systems Diagnostics devices list to select Spm0 and press the Calibrate button Measure the connected voltage with digital voltage meter that shows at least 3 decimals and enter the value to First Potential V field Make sure that reading in First value native units has stabilized and press Next button 10 KSV SPOT Manual Rev 1 0 Instruments KSV SPOT Surface potential Calibration First value native units 1 Apply some known voltage between a test electrode and 4 reference connector around 1 2 W When Second value native units the reading i stabilized click NEXT TED SEA a are button 2 Then apply another voltage between the test electrode and the reference First Potential 1 connector around 1 2 274 0 3 Fill out the voltage values and click HET button again Second Potential i 4 Wait until the calibration is completed 2 754 Hent Cancel Change DC power supply connection to vice versa ground should be connected to Counter Electrode and positive voltage to RCA connector Enter complement value negative to Second Potential V field
10. measuring head by switching the toggle switch to up position The complete system should be powered on at least one hour before starting an 15 KSV SPOT Manual Rev 1 0 Instruments KSV SPOT experiment and the Spot head should be turned on at least 10 minutes before starting an experiment Clean the water surface with utmost care before spreading the substance The surface potential is much more sensitive to impurities than the surface pressure Always zero the measuring head before spreading any substance on the surface The measuring head can be zeroed by choosing Zero SPM from the Controls drop down menu in the KSV LB Control Software window PSY LE Deia Siia ig rT zinj Fie EH Crimi Hai Treagnl Bi jhi B jahim Bni irj Self OD pe ifd ra SP fil a0 fe fe Te lS i le ee ee io Semple Interval jr Baars S BHT prea Ester Beli ide Bri i More hd Hone fe Moret po Eten Sp After spreading the substance one should wait a sufficiently long time before the compression is started Otherwise all of the solvent may not have evaporated which can influence the outcome of the experiment Spread as small amount as possible of the substance on the subphase The surface potential often increases rapidly long before the surface pressure starts to increase An ideal shape of the trough used with surface potential measurements is long and reasonably narrow The barrier s should never be driven closer than ca 1 cm to the meter head
11. molecular area A2 molecule Surface pressure and Surface potential isotherm of Stearic acid on a subphase with pH 4 Surface potential mV 10 20 30 40 50 Mean molecular area A2 molecule Three separate measurements of Stearic acid monolayers on a water subphase pH 4 demonstrating the reproducibility of the KSV SPOT surface potenital measuring head 18 KSV SPOT Manual Rev 1 0
12. ndow open the Edit drop down menu and choose Device parameters The Instrument Parameters window will then appear Barrier Type ksv 200030005000 Dipper Type Standard model Alemate head parameters TumSpdup TumSpdD own dhi 1367 dd 1600 dum 35 0 dim 150 du 10 0 dumin 35 0 Balancel Probe one a Perimeter 20600 mm Balance Probe Name Wilhelmy Perimeter 23 800 mm Usage of balances f Ball gt Trl and Bal2 gt Tre C Ball and Bal2 gt Tr C Ball and Bale gt Tr2 Brewster angle microscopy Surface potential meter l Sound card Spm connected Enable RS BAM Contral Enable DataSacket transmit OF Cancel In the Instrument Parameters window uncheck the Sound card Spm connected box in the lower right corner Then press OK and close all the windows and the KSV WinLB software Now everything is set for surface potential measurements For a measurement start the KSV WinLB software To continue with the measurement place the KSV SPOT measuring head approximately in the middle of the trough with a sufficient distance from the trough edges Hereafter place the counter electrode in the subphase and the vibrating plate a few mm from the subphase surface If the vibrating plate accidentally touches the subphase and gets wet it does not do any harm to the measuring head The plate should just let to dry out before starting a new experiment Start the
13. ng the real time experiment the surface potential data is automatically recorded to the hard disk and it can be displayed afterwards Presupposed that the surface potential measuring head has been started and zeroed from the KSV LB Control Software and the control window has not been closed The collection of surface potential data is stopped when the chosen LB experiment is completed or stopped When a new measurement is performed the only thing to remember is to zero the surface potential again before any substance is spread on the fresh and cleaned gas liquid interface After the measurements have been done all facilities for data point presentations in the KSV WinLB software graph print and export of the data points etc can be used for the collected surface potential data 17 KSV SPOT Manual Rev 1 0 Instruments KSV SPOT 7 Example measurements Stearic acid has been used as the monolayer forming substance because it has been studied by a large number of research groups and its characteristic properties are largely known In these example measurements a pure water subphase with pH 4 have been used The obtained surface potential values are 349 2 mV This is in good accordance with the literature values The reproducibility of the KSV SPOT measuring head is very good which is seen from the low standard deviation of the results No Surface pressure mN m gt Aw enua od avens 2 o 10 20 30 40 50 Mean
14. the differences in Volta potential between various metals This condensator is often also called the Kelvin probe Yamins and Zisman applied this method to study monomolecular films Since then this method has widely been used for determining the surface potential of monolayers The design of KSV SPOT is based on these main ideas The main application area for KSV SPOT is in monolayer studies but due to its stand alone property it is also suitable for other areas where surface potential measurements are required Insoluble monolayers at the gas liquid interface are generally characterized by measuring the surface pressure 7 area A isotherm The 7 A isotherm is characteristic for any given ampiphile or mixtures of ampihphilic molecules Many substances show a variety of different monolayer phases gt The major phases are easily recognized in the isotherm as sharply separated regimes with different compressibility Although the measurement of 7 as a function of A can give valuable information about monolayers area per molecule collapse pressure phase transition pressures and temperatures mixing behavior of two or more amphiphiles etc it may not reveal all of the desired information A complementary and a more sensitive way to characterize a floating monolayer is to measure the changes in the surface potential AV This is possible due to the fact that an insoluble monolayer at the gas liquid interface changes the surface potential
15. through this interface This change equals the Volta potential between the surface of the liquid and that of the metal probe Normally only the changes in AV due to the presence and changes in the state of the monolayer are measured In this case the clean liquid surface is fixed to the value 0 mV and the spread monolayer gives the obtained AV AV can be used to determine the composition of the monolayer the dissociation degree of an ionisable monolayer the orientation and reorientation of the monolayer molecules at the interface during compression ee By measuring AV one can also reveal the interaction between the molecules in the monolayer much earlier than by measuring m The type of deposition that has occurred for LB films X Y or Z deposition has also been determined by measuring the AV Yamins H G and Zisman W A J Chem Phys 1933 1 656 Amphiphile A substance containing a hydrophilic water loving and a hydrophobic oil loving part The hydrophilic part can for example consist of an alcohol carboxylic acid amine or phosphorylcholine groups and the hydrophobic group s is generally composed of hydrocarbon chains Binks B P Adv Coll Interf Sci 1991 34 343 Roberts G G Langmuir Blodgett Films Plenum Press 1990 Gaines G L Insoluble Monolayers at the Liquid Gas Interface Wiley Interscience 1966 Lind n M PAD thesis Abo Akademim Univerity Finland 1996 Vogel V And M bius D J
16. ument allows you to perform the experiments and further to graph and print test results The data is stored to the computer hard disk and can easily be retrieved and analyzed later The data can be exported in a form that is understood by the most common data reduction software This manual provides information how to install and use the KSV SPOT In order to obtain the maximum performance from the instrument read this manual and keep it available for reference The hardware for the KSV SPOT is manufactured to the highest quality standards and when used properly it should yield a trouble free use for a long time KSV SPOT Manual Rev 1 0 Instruments 2 Technical Specifications Measuring principle Dynamic range Sensitivity Response time Inaccuracy Height dependency Drift Probe diameter Sensor head dimension Mounting Computer requirements KSV SPOT Manual KSV SPOT Vibrating plate capacitor method 4 to 4 V mV 2 seconds 3 mV 10 mV mm Negligible in air 3 mV h with subphase 16 mm 130 x 43 x 95 mm Height adjustment 100 mm IBM compatible running Windows 2000 XP Vista Rev 1 0 Instruments KSV SPOT 3 General introduction If there exists a difference in the electrostatic potential between two surfaces and these are put in movement relative to each other there will be a current flowing through an external circuit This kind of condensator was used by Volta and Kelvin to study
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