Most modern method to measure the surface and interfacial tension of liquids
Principle is based on the analysis of the shape of pendent and sessile drops or buoyant and captive bubbles.
The instrument is well suited to determine the contact angle of liquids on solid surface. The apparatus is driven by a modern Windows software.
Modular extension for different applications.
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Instrument Parts |
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- Basic platform on which all parts are safely mounted
- Computer controller dispenser
- Adjustable temperature controlled measruing cell
(low temperature range 10 to 80°C, high temperature range 10 to 1000°C)
- CCD-camera with fixed objectives
- High-performance frame grabber installed in the PC
- Cold back-lighting with continuously adjustable intensity
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Technical Data |
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| Range of surface and interfacial tension |
1 to 1000 mN/m
Resolution: ± 0.1 mN/m |
| Range of contact angle measurement |
10° to 180°
Accuracy ± 0.3° |
| Optics |
Fixed objective
CCD-camera, max. resolution of 768 x 576 pixels
Optical distortion: < 0.05 % |
| Frame grabber |
Nl high-quality digitising board
Transfer rate: 25 images per second |
| Software |
Windows software
(free update over 1 year after purchase) |
| Measuring options: |
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• Pendent drop, buoyant bubble |
Surface / interfacial tension
Dilational elasticity and viscosity |
| • Sessile drop |
Contact angle, surface tension |
| • Drop and bubble oscillation |
0.001 to 1 Hz |
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Features of the Instrument |
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This instrument allows measuring quite a number of interfacial properties. In addition to the properties of a standard drop and bubble instruments the PAT-1 (Profile Analysis Tensiometer) from SINTERFACE allows unique experiments and gives access to quantities not easy available by other methods:
- Surface and interfacial tension of liquids
- Static and dynamic contact angle according to the sessile drop method
- Surface rheological studies to measure the dilational elasticity and viscosity
- Capillary pressure measurements for iso-dense liquid/liquid systems
- Short time interfacial tensions with extra module DPA-1
- Direct drop-drop, bubble-bubble, and dropbubble interactions with a special micro manipulator (extra equipment DBMM-1)
- Fast oscillations with extra module ODBA-1
- Time dependence of all measured quantities
- Online temperature control
- Area or volume can be kept constant during the measurement
- 0.1 s resolution over a period of seconds up to days
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Main features of the software |
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- On-line interfacial tension/contact angle calculation
- Calculation of the surface free energy of solids according to the equation of state by Li and Neumann
- Control of the dosing system for accurate changes of a drop or bubble (transient or harmonic changes)
- Control of a piezo system (additional equipment) for active and very accurate control loop to keep constant either volume or area of drop or bubble
- Smooth oscillations with piezo system harmonic and transient relaxation experiments
- Calculation of the dilation rheological parameters from relaxation measurements via Fourier analysis
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