Measuring Contact Angle,Interfacial Tension And Wettability in Electronics Industry

Electronics industry provides electrical circuits involving active electrical components. Integrated circuits that are used in electrical and electronic devices are built on wafers made of semiconductor materials. Silicon is the most used semiconducting material. Silicon wafers are made of extremely pure silicon, which requires a high quality control. Polymers are also used in the electronic industry as insulating layers in the fabrication of chips and chip carriers. By using our product brand Attension, Tensiometry can be widely utilized in the electronics industry to characterize different material properties.
Application examples include:

• Cleanliness of silicon wafers and circuit boards is an important factor to ensure the optimized functionality of the final product. Contact angle measurements with optical tensiometers can be used to study cleanliness of silicon wafers and circuit boards during the manufacturing process. • Semiconducting wafers are typically processed with protecting coatings. Quality and uniformity of these coatings can be studied with contact angle measurements. • Wettability and interfacial tension are important characteristics of soldering systems used in electronics industry. The molten solder alloy needs to wet both metal surfaces in order for the surfaces to link. Wettability of molten solder on metal can be defined by contact angleforce tensiometer. measurements with

Measuring Contact Angle & Surface Tension In Energy Industry

Real-World Implications Case Studies Within the Oil & Gas industry, several case studies exemplify the advantages derived from conducting surface property measurements

Enhanced Water-Oil Separation 

Scenario: In an offshore oil production platform, the production stream includes a significant amount of water, which forms an emulsion with the crude oil due to high surface tension. Application: By lowering surface tension using appropriate surfactants, contact angle and surface energy measurements can guide the selection of the most effective chemicals. This optimization improves emulsion destabilization, allowing for more efficient water-oil separation and reduced energy consumption during processing

Scenario: Enhanced oil recovery (EOR) methods are employed in a mature oil reservoir to recover more oil. Contact angle measurements are used to assess the wettability of the reservoir rock. Researchers discovered that the rock has mixed wettability characteristics. Application: By altering the contact angle using specific surfactants or polymers, surface energy measurements help design a more effective EOR strategy. This increases oil recovery by modifying the interaction between the reservoir rock and injected fluids

Scenario: Offshore pipelines are exposed to harsh seawater conditions, leading to corrosion and reduced lifespan. Engineers apply hydrophobic coatings to the pipeline surfaces. Sliding angle measurements help evaluate the performance of these coatings. Application: By achieving a low sliding angle, the coatings effectively repel water and reduce the risk of corrosion, extending the life of the pipeline and reducing maintenance costs

 

Kulim Electrochemical Setup

SPR Kulim

Kulim KHT SPR

Langmuir-Blodgett film characterization in air using surface plasmon resonance

Introduction
The ability to assemble ordered molecular films with tailored
functionality over macroscopic lateral dimensions provides
exciting and unique opportunities in many practical and
commercial applications. Sensors, detectors, displays and
electronic circuit components are just a few examples. This
well known technique is referred to as Langmuir-Blodgett
(LB) deposition, where films of functional molecules,
nanoparticles, nanowires or microparticles are spread at the
air-water interface, compressed and transferred to a solid
substrate. Compared to other organic thin film deposition
techniques, such as thermal evaporation, sputtering,
electrodeposition, molecular beam epitaxy, layer-by-layer
or self-assembly, LB is much less limited by the molecular
structure of the functional molecule. This means that it
is often the only technique that can be used for bottomup
assembly in nanotechnology and functional materials
applications. The aim of this note is to demonstrate that
SPR-Navi is ideal for the ex situ
investigation in air of mono- and multilayer films of stearic
acid deposited on a gold surface.

Experimental
The gold-coated glass slides used in the SPR
measurements were cleaned by immersion in a boiling
1:1:5 NH3OH:H2O2:H2O for ten minutes, flushed thoroughly
with ion exchanged water and blown dry with nitrogen.
Monolayers and multilayers of Cadmium Stearate (SACd,
(C17H35COO)2Cd) were deposited via the LB technique
(KSVNIMA System 2) on cleaned gold slides,

Complete SPR curves were measured after depositing one, three and five layers of
SACd on separate gold slides.

Kulim ASTM D971

ASTM D971 standard test method for interfacial tension of oil againstwater by the ring method

This application note describes how the Attension Sigma 702ET

can be used to measure interfacial tension of oil against water

according to the ASTM D971 standard.

Description of the standard

This application note describes the measurement of interfacial

tension between oil and water under non- equilibrium conditions

by using the ring method according to the ASTM standard. The

Attension Sigma 702ET allows a precise characterization of wateroil

interfacial tension with this standard. The method is especially

important in petroleum industry as it can be used to determine oil

purity.

In this interfacial tension measurement the platinum ring is lifted

through the water-oil interface. The oil is lying on the water surface

due to the density difference of these two liquids. Water has a

higher surface tension than the oil and therefore force is needed

to detach the ring from the water surface. The force measured is

used to calculate the interfacial tension (mN/m) between oil and

water. The measurement is made within 60 seconds after formation

of the interface with a tensiometer determining tension

between 0-100mN/m. The Sigma 702ET fulfills the requirements

of the ASTM D971 standard. The instrument allows the measurement

do be done fully automatically. A high interfacial tension

value (40mN/m) [1] indicates the absence of undesirable polar

contaminants in the hydrocarbon fluid which means that the fluid

is immiscible with water. A decrease in interfacial tension occurs

for example due to accumulation of contaminants or due to formation

of oxidation by-products. The impurities in the hydrocarbon

fluid encourage the oil to mix with water.

ATTENSION SIGMA 702ET

General applications

The ASTM D971 standard is used to determine the possible

contaminants of hydrocarbon fluids. The purity of hydrocarbon

fluids is important in many industrial areas, such as in aviation,

diesel fuels and transformer oils. For example in aviation, jet fuel

needs to be highly purified as water or dirt contaminations can

cause serious danger in flight safety. Surfactants in jet fuel can

cause the lifting of rust in storage tanks as well as absorption of

water on coalescing surfaces [2]. The ASTM D971 standard is also

a useful indicator of the cetane number of diesel fuels [3]. The

cetane number of diesel fuels is used to define the quality of

combustion during ignition.

KULIM Hi-Tech Sdn Bhd

Association and solubility studies of mixed polyglycol ether surfactants in water

Bassem M. Bajouk, Rolf O. Sköld

Department of Applied Surface Chemistry, Chalmers University of Technology, Kemivägen 10, SE-412 96 Göteborg,Sweden

The effect of varying the molecular structure and the type of counter ion of polyglycol ether based anionic

surfaceactive components on the processes of phase separation, adsorption to the air-water interface and

molecular association in aqueous model metalworking formulations containing a polypropylene glycol was

studied. Phase separation and micellization were studied via static surface tension measurements and by

using an instrument, which enables the automatic scanning of temperature and concentration dependent pH,

turbidity and conductivity data. The anionic surfactants investigated were highly water-soluble and the

surface tension isotherms of all formulations were found to display a common anomalous trend characterized

by an initial maximum in the Gibbs surface excess function followed by a plateau region before a second

maximum occurs just before the concentration taken to indicate micellization. The aqueous mixtures in most

cases displayed concurrent phase separation and micelle formation, which has to be taken into account when

comparing critical micelle concentrations (CMCs). The present availability of parallel data, turbidity data in

particular, allowed incipient phase separation to be detected. This is a circumstance, which would otherwise

pass unnoticed, since it is not visually detectable. Results are considered industrially useful since the control

of the isotropic temperature - concentration space is a key aspect in the design and fine-tuning of

environmentally benevolent aqueous functional fluids for specific applications.

© 2002 Elsevier Science B.V. All rights reserved.

Colloids and Surfaces A: Physicochem. Eng. Aspects 212 (2003) 65 -/77

SPR Navi™ 220A - THE AUTOMATED MP-SPR

SPR Navi™ 220A is the top of our line. Choose SPR Navi™ 220A, if you want to perform high-throughput MP-SPR with minimum dead-volumes and increased measurement confidence. As shown in the comparison, it is fully automated. Also here, to fully enjoy the MP-SPR, we recommend the additional set of lasers.

Key Features of SPR Navi™ 220A:

True Goniometric SPR

Unlike most SPR systems, SPR Navi™ 220A is a true goniometric SPR. This eanbles a wide angular scan range ( = 40–78°) that produces a complete SPR curve with absolute angle information. The true goniometric SPR configuration confers great advantages as it widens the range of refractive indexes at which you can measure, allowing you to characterize surfaces in gas and/or liquid. It also allows you to check the quality of user-defined surfaces before sample injection, providing you with additional evidences. In other words, the wide angular scan range makes SPR Navi 200 an extremely sensitive and versatile characterization instrument.

Customizable flow cell

SPR Navi™ 220A comes with dual measurement channels for in-line referencing or duplicate measurements. In addition, the easily accessible flow-cell can be customized for user-specific experiments, thus broadening your experimental capabilities. For instance, BioNavis can provide electrochemical flow cells or flow cells equipped with optical fibers for surface illumination. The flow cell shape can also be customized to tailor the flow dynamics to your needs.

Flexible sensor-slide system

With the SPR Navi™ 220A instrument, you can use the innovative sensor-slide holder for easy “drop-in” placement of your sensor-slide into the instrument. It allows users to change surfaces within seconds, making SPR Navi™ 220A an extremely convenient instrument to work with. The sensor-slide holders can be labeled and used for long-term storage of your custom-modified surfaces. Sensor-slides can be modified outside the instrument, with a great number and combination of layers, prior to the actual analysis. This unique removable sensor system provides additional flexibility. It allows you to combine SPR data with other widely used techniques to provide supporting information, including surface topography, surface wettability, chemical composition, photochemical processes, swelling, adsorption...

Contamination free MP-SPR

The proprietary optical elastomer in the SPR Navi™ 220A finally does away with the need for messy and potentially contaminating index-matching oil. The result is a contamination-free environment for your measurements. The optional immobilizer, a horizontally oriented stand-alone flow cell, can be used for in-situ functionalization of SPR slides. This further minimizes the risk of cross-contamination and enables minimal sample depositions.

Contact Angle.

DEMO.

KHT did a Demo in one of our Top Universities.

Theta with KSV software. We got 3hrs to prove.

Surface Plasmon Resonance SPR BioNavis 200

Dip Coating, LB and LS methods have been shown to be excellentmethods for controlled preparation of thin films graphene and graphene oxide. The methods offer great amount of control for depositing dispersed SG and SGO produced by the liquid exfolia-tion methods. As the liquid exfoliation methods are recognized as some of the most potential methods for producing graphene in industrial scale, these deposition methods are of great impor-tance in graphene research.We introduced more thoroughly two powerful optical methods for characterizing graphene films before and after deposition, PM-IRRAS and SPR. With the KSV PMI 550 it was possible to record detailed IR spectra of floating and deposited layers to determine the chemical composition. The SPR Navi 200 was capable of characterizing the thicknesses and the complex refractive indices of the deposited layers. It was possible to distinguish single sheet and aggregated graphene from each other.

Potentiostat ACM

The potentiostatic test is usually performed to determine resistance to pit initiation at a given potential and to simulate galvanic situations using any of Gill AC 8 12 Field Machine and manual potentiostat set to a stable potential whilst recording the current. In the study of pitting the cyclic sweep method can have problems related to sweep rate and too much pitting propagation before sweep reversal. The use of individual samples held at potentials around the suspected pitting potential will allow the correct determination of the pitting potential. For example the graph below shows current versus time for samples polarised at different potentials.

Corrosion Testing and Study

Cortest was formed in 1977, and since then, Cortest has grown to include a family of related companies providing corrosion testing equipment, corrosion testing services, technical consulting, field service, and training courses.

Cortest Incorporated specializes in a systems approach to meet all of your corrosion testing needs. We manufacture a comprehensive line of corrosion testing apparatus and support equipment that combine to form complete testing capabilities for both static and dynamic test conditions. It is this ability to ensure equipment compatibility and proven system performance which makes Cortest a unique single source of supply for your test equipment needs.

For the past 25 years, Cortest has manufactured laboratory corrosion testing equipment, as listed below. Please select your areas of interest for additional information.

Proof Rings and accessories, for testing of stress corrosion cracking in accordance with NACE Test Standard TM-01-77-90. The Cortest Proof Rings provide an economical but effective way to accurately determine the Stress Corrosion Cracking (SCC) susceptibility of metals in different environments.

Autoclaves for high temperature and high pressure tests at 5,000 psi (350 bars) and 600°F (315°C) (up to 20,000 psi (1400 bars) and 1100°F (600°C) for specific systems).

Slow Strain Rate Test (SSRT) systems with the CERT machines for Constant Extension Rate Tests from 10^-5 to 10^-8 in/sec, including a variety of environmental chambers and controls, and featuring the new CVI (Computer Virtual Instrument).

Corrosion Fatigue Test system extending the capabilities of the CERT machine and simulating a wide range of loading cycles.

Recirculating Test Loop to refresh autoclave systems.

Multiphase Test Loop for studying behavior of materials under multiphase flow conditions.

Training Courses on corrosion, metallurgy, and multiphase flow.

Instrumentation/Sensor Design. Customized instrumentation and sensors for corrosion load, steam, pH, O₂, H₂ and other measurements.

Corrosion Measurement in laboratory equipment.

Custom Equipment for specialized applications. Aside the large range of laboratory equipment available, Cortest has a long experience in customized laboratory equipment. The combination of electrochemical and mechanical testing has been meeting the individual needs of corrosion engineers for all kind of corrosion testing requirements.

Advertisement of SPR Navi 200

The stand-up poster of Bio Navis product which is SPR Navi 200 is being displayed at one of our Malaysian top universities' souvenir shop to attract potential lecturers or students.

In situ investigations on enzymatic degradation of poly

SPR Bionavis

Q-Sense 4 sample in one Run workhorse

The present study leads to the following conclusion. QCM-D

and SPR can be used to investigate the enzymatic degradation of

a polymer film in real time, where the changes in mass and morphology

of the film can be well described by the frequency and

dissipation in QCM-D as well as the SPR signal response. PCL

with small crystallites degrades in a way of layer-by-layer with

pseudo first-order degradation kinetics. The degradation of PCL

with crystalline lamellae exhibits two-stage kinetics, which relates

to the degradation of amorphous PCL and PCL crystallites,

respectively. The former degrades more quickly than the latter,

leading the film to be microporous

Surface Plasmon Resonance (2 Channels/exchangeable cuvette)

BB Band played superbly that night ..... Impressed .... Especially Jorma...

Advantages of SPR NAVI 200

• Increased angular range that enables simultaneous gas and liquid-phase measurements

• Contamination-free index matching with a proprietary optical gel

• “Drop-in” sensor plate design• Integrated high-performance liquid handling

• Dual measurement channels for in-line referencing and/or duplicate measurements

• Support for a second laser wave length, for simultaneous determination of RI and thickness

• Automated determination of measurement parameters for sensogram measurement

• High-accuracy sensogram (kinetic) measurements• Easy use of user-defined/modified surfaces

Application notes are provided at our web site: www.bionavis.com

Kulim Kht DP Meeting Helsinki

An Introduction to Biophysical Characterisation

using Dual Polarisation Interferometry

Dual Polarisation Interferometry (DPI) is a highly versatile, powerful analytical technique for

biophysical characterisation of proteins and other biomolecules. It extends the typical dynamic

measurements of conventional biosensors by including an additional quantitative, sub molecular,

conformational measurement.

DPI delivers a unique perspective on biochemistry, linking conformational changes to biochemical activity at a resolution normally associated with ‘big physics.

Two polarisations of light are passed through the

sensor which consists of an upper ‘sensing’ layer

and an embedded ‘reference’ layer. The output

from each of the layers then combine producing two

interference patterns which are detected by a

camera.

As molecules bind (or change shape) on the

surface of the ‘sensing’ layer, they are probed by

the evanescent field from the ‘sensing’ surface.

This, in turn, changes both interference patterns. As

material binds, the interference pattern shifts one

way. As material is removed from the surface, the

interference pattern returns.

The AnaLight® Resolver software automatically analyses both sets of data and outputs the real time

changes in the thickness, density and mass of the molecular layer. All of the calculations are based on

classical optics theory and have been independently validated by, amongst others, the National

Physics Laboratory (NPL) in the UK. www.farfield-group.com

Goniometer Kulim Kht KSV

Remembering 2010 Iceland Volcanic Ash

DATE FRIDAY 16, 2010. TIME 16 HOURS

START FROM GOTHENBURG SWEDEN TO LONDON UK.

ENTERING DENMARK

ENTERING GERMANY

ENTERING NETHER LAND

ENTERING BELGIUM

ENTERING FRANCE- DIRECT TO Z1 DU PORT DUNKERQUE

ENTERING UK- DOVER PORT TO DOVER TRAIN STATION

REACH ST. PANCRAS INTERNATIONAL ON SATURDAY 17. 2010 8.30 HOURS. 1600KM

l AM BEING HOLD BY BRITISH M16 OUTSIDE ST. PANCRAS INTL TRAIN STATION

SUSPECTED ME AS TERRORIST, BUT THEN THEY LET ME GO SINCE I GOT NOTHING ON ME . MEET ENGLAND PM GORDON BROWN OUT SIDE THE TRAIN STATION.

PM IS ON HIS ELECTION CAMPAIGN VISITING PUBLIC AT THE TRAIN STATION.

ALL BECAUSE OF VOLCANIC ASH FROM ICELAND.

SPR Navi 200 specification

SPR Navi 200 specification

1. True goniometric principle, enabling to record the full SPR curve for thickness and refractive index model-ing

2. Wide SPR angle range (40 degrees to 78 degrees) allowing to measure both liquid and gas samples with the same instrument

3. Proprietary SPR slide holder allowing easy change and use of SPR gold slides

4. Easy drop-in action in placing the SPR slide in the instrument

5. Easily removable and easily customizable flow cell

6. Modular design allowing to add an autosampler and other features, such as multi wavelength function, at the later stage

7. No need to use messy and inconvenient index matching oil because of the proprietary index matching gel

8. Open design allowing the customer use their own fluidics and flow control (our pump can easily be by-passed)

9. Build in peristaltic pump and optional syringe pump available

10. Easy to use slide holder allowing quick and easy slide replacement without any tools

11. External immobilizer allowing the instrument be used while immobilizing the gold surfaces

12. Possibility to use two lasers with different wave lengths and/or even IR lasers

13. Optional electrochemistry flow cell

Contact Angle meter/Gonimeter: Theory

Contact Angle: Theory

The following is a short introduction to the concepts involved in the measurement of contact angles. Included is an introduction to the techniques involved and some practical advise. For those interested in further information a list of references appears at the end of this chapter.

What is contact angle?
Contact angle ,q, is a quantitative measure of the wetting of a solid by a liquid. It is defined geometrically as the angle formed by a liquid at the three phase boundary where a liquid, gas and solid intersect.

It can be seen from this figure that low values of q indicate that the liquid spreads, or wets well , while high values indicate poor wetting. If the angle

q is less than 90 the liquid is said to wet the solid. If it is greater than 90 it

is said to be non-wetting. A zero contact angle represents complete wetting.

Hysteresis: For any given solid / liquid interaction there exists a range of contact angles which may be found. The measurement of a single static contact angle to characterize the interaction is no longer thought to be adequate. The value of static contact angles are found to depend on the

recent history of the interaction. When the drop has recently expanded the angle is said to represent the ‘advanced’ contact angle. When the drop has recently contracted the angle is said to represent the ‘receded’ contact angle. These angles fall within a range with advanced angles approaching a maximum value and receded angles approaching a minimum value.

The difference between the maximum(advanced) and minimum(receded) contact angle values is called the contact angle Hysteresis. A great deal of research has gone into analysis of the significance of hysteresis. It has been used to help characterize surface heterogeneity, roughness and mobility. You are recommended to the papers listed in the reference of this section for details on experiments regarding hysteresis.

Contact angle can also be considered in terms of the thermodynamics of the materials involved. This analysis involves the interfacial free energies between the three phases and is given by:

g_lv cos q = g_sv - g_sl

where g_lv ,g_sv and g_sl refer to the interfacial energies of the liquid/vapor, solid/vapor and solid/liquid interfaces.

Coatings: Coatings may be applied to any solid for testing contact angles. Microscope slides and cover slips make ideal supports for such an application. Ideally the coating should be applied to all sides. If you reduce the size of your sample by cutting after coating you will expose part of the support which is not coated. This will introduce an error in your data especially if the cut side is rough. Your data may be consistent enough to compare between similarly treated samples but the absolute values will not be accurate.

Tensiometer Kulim Kht

Installation in Malaysian Top University complete system

Potentiostat LPR technique

The LPR technique is the most frequently used being both quick and easy. A small sweep from typically -10 mV to +10 mV at 10 mV/min around the rest potential is performed. The resulting current/voltage plot usually exhibits a straight line the inverse slope of which is proportional to the corrosion rate. The Gill AC Gill 8 and 12 the Field Machine the Pocket Machine the LPR meter and the Bubble Test software all use this method.

Kulim Kht Contact Angle/Goniometer

Captive bubble method in contact lens studies

Contact lenses are widely used and hydrogel contact lenses are the most

prescribed type of contact lenses around the world. Hydrogel lenses are made from

hydrophilic polymers, such as polyhydroxyethyl. Contact lenses should have certain

characteristics to avoid discomfort during wear. These include an adequate oxygen

permeability, lens motion and surface wettability. A fairly recently discovered

material for contact lens manufacturing is the silicone hydrogel, which is suitable for

long term use as it has improved oxygen delivery on the ocular surface. However,

this material has been reported to have reduced wettability compared to the other

materials used in hydrogel contact lenses.

The wettability of a lens is measured on the abilities of the lens to support a

continuous and rupture-resistant tear film on its surface. A lens with a limited

wettability is uncomfortable and has a reduced visual performance. Therefore it has

been a major investment for the contact lens industry to develop a soft lens surface

that is highly wettable in the ocular environment.

How to study the wettability of contact lenses?

Contact angle measurement is the most common method used to characterize

wettability of solid surfaces. There are a variety of contact angle techniques that can

be used for this purpose: the sessile drop method and the captive bubble method.

Sessile drop and captive bubble methods can also be used simultaneously to

measure the different contact angles of a lens. Sessile drop method can be used to

examine the advancing contact angle and captive bubble method to obtain the

receding contact angle. Both of these contact angles can also be obtained only by

captive bubble method. Captive bubble method is very useful as it is possible to

maintain fully hydrated conditions on the lens surface during the experiment. This is

essential as the drying of the lens causes the setup to be far from the ideal

conditions. Figure 1a illustrates the sessile drop method, where a drop of water is

replaced on a glass slide. The contact angle obtained with this method was 140°. In

Figure 1b the contact angle of an air bubble in water is obtained with the captive

bubble method and it is calculated to be 40°. Contact angle hysteresis is the

difference between the advancing and receding contact angles. It can be used to

characterize the surface roughness, chemical heterogeneity, re-arrangement of

molecules at the surface, solid swelling and mobility. In highly water wetting lenses

the contact angle hysteresis is eliminated and both the advancing and receding

contact angles approach zero.

Captive bubble technique

In the captive bubble method the contact angle is measured by placing a bubble of

air onto the lens surface with a capillary while the lens is immersed in a liquid.

Preferably the lens should be soaked in liquid for a couple days before the

measurement takes place in order to get the lens fully wet. The conditions in this

experiment should mimic the in vivo conditions as good as possible, meaning that

the liquid used in the contact angle experiments should be close to the real nature

of a tear film in the eye. The tear film is composed of surface active components

such as mucin and lysozyme.

Receding and advancing contact angles are both important measures of contact

lens wettability. A receding angle forms as the water phase moves away from the

capillary. This corresponds to the situation when the eyelid is open and the tear film

starts rupturing on the lens. The advancing contact angle develops as the water

phase moves towards the capillary. This is the case when the eyelid closes and the

tear film on the lens starts to recover.

A solution for finding improved wettability?

With captive bubble method contact angles of lenses can be measured in different

solutions to obtain the most ideal solution that wets the lens best. Some have

reported that significant change can’t be seen in whether the solution is pure water

or a liquid containing surfactants (like the contact lens solutions on the market).

Also studies of different coatings to improve the lens wettability have been made.

Protein coatings have found to be successful in improving the wettability of contact

lenses. Protein coatings resist the tear protein adsorption and deposition into the

lens.

Biolin Q-Sense Kulim Kht QCM-D

QCM-D Technology

By collecting both the dissipation and the resonance frequency of a quartz crystal,
QCM-D technology can be used to characterize the formation of thin films (nm) such as proteins, polymers and cells onto surfaces, in liquid. This is QCM-D, Quartz Crystal Microbalance with Dissipation monitoring, Q-Sense's proprietary sensor technology.

In liquid, an adsorbed film may consist of a considerably high amount of water, which is sensed as a mass uptake by all QCMs. By measuring several frequencies and the dissipation it becomes possible to determine whether the adsorbed film is rigid or water-rich (soft) which is not possible by looking only at the frequency response. The amount of water in an adsorbed film can be as high as 95% depending on the kind of molecule and the type of surface you are studying. Picture elongated molecules - if they would adsorb flat on the surface, little water will be coupled to the molecules. However, if they adsorb standing up at the surface, lots of water will be coupled. With QCM-D the kinetics of both structural changes and mass changes are obtained simultaneously.

Would you like to ask specific questions or gain more information about the QCM-D technique? You are welcome to contact us at any time.

The QCM-D Principle
Unlike all other QCMs, QCM-D monitors the response of the freely oscillating crystal, which is faster and more accurate than the usual frequency sweep principle.

ASTM D971 standard Tensiometer Kulim Kht .

Performing an interfacial tension measurement

between water / oil according to ASTM D971 standard.

1. Check the instructions in section 5.1 and make necessary preparations.

2. Set oil density to correct value. You may also measure the density of the

oil (see section 5.2).

3. Make sure that the correction method of your preference is selected. You

can change the active ring correction method from Adjust parameters

menu. To be strictly compliant with ASTM D971 standard, choose

Zuidema-Waters. However, Huh-Mason is a more modern method that is

generally regarded more accurate.

4. Pour distilled water at a temperature of 25 ± 1°C into cleaned sample

container to a depth of 10 to 15 mm. Place it in to the middle of the

tensiometer platform. Make sure no foam is present at the water surface.

If foam is visible, discard the water. Foam indicates that the water is

contaminated or that the vessel is not clean.

5. Mount the ring in the tensiometer hook. If the oil to be measured is denser

than water, the measurement must be performed in Push Mode1, and the

supplied weight therefor needs to be attached to the ring before mounting

the ring.

6. Select "Measure oil interface" from the menu selection and press the OK

button. Sigma will now measure automatically the surface tension of the

water. Wait until the measurement has completed. If the measurement

was successful, the ring will automatically descend back into the water,

except in the case of Push Mode measurement with dense oil, however,

the ring will remain about 5 mm above the water.

7. When the ring has stopped moving, carefully layer the oil on the surface of

the water, until an oil layer of at least 10 mm is reached2. Do not move

the sample container from tensiometer platform, nor move the ring.

8. Press the OK button right after the oil pouring is finished. The tensiometer

will then wait for 29 seconds (as the standard requires a wait between 29

and 31 seconds), until it starts the measurement of the interfacial tension

between water and oil. Wait until the measurement has completed.

9. Interfacial tension value is shown on the display.

As the ring is pulled through a surface or an interface, a curve is plotted,

showing the tension value calculated from the balance reading at each

instant. The highest value encountered will be displayed as the result of the

measurement.

1 If the oil is denser than water, it forms a layer below water and interfacial tension must

measured by pulling the ring downwards from water to oil; hence the name Push Mode. The

case of Push Mode measurement is not explicitly addressed in ASTM D971 standard.

2 Layering the oil should not take more time than 30s since completing the entire interfacial

tension measurement have to be done within 60s ±10s

ICENV 2010 IN PENANG