Analysis software FAMAS
The analysis software FAMAS is an integrated software performed on KYOWA’s contact angle meters and dynamic surface tensiometer BP series. The following features are part of the software:
Sessile drop method
Typical contact angle measurement of droplets on a leveled surface. Measurements in static and dynamic mode in time function are available.
Sessile drop method in time function
Sequential measurements of the contact angle at a certain time interval. 30fps, 60fps, and 333fps camera systems are available depending on the model and an optional high-speed capture system up to 1,000fps is also available. Application: Initial spreading, absorbing property, effect of surface active agents
Extension/contraction method
The extension/contraction method is also known as the captive drop method.
Advancing and receding angles are measured while increasing or decreasing the droplet volume captured by the needle on the solid surface. An automatic dispenser system that ensures a constant flow rate for high reproducibility is highly recommended to perform this measurement method effectively.
Applications: Coating properties, repellency, characterization of droplet hysteresis
Sliding method
The sliding method is also known as the tilting method or roll-off method. Advancing and receding angles are measured while an external tilting stage tilts the instrument up to an angle of 90 degrees. The inclined angle at which the droplet starts to slide or roll off from the solid surface is called the sliding angle. At the same time, the adhesive energy between the droplet and the solid surface is analyzed. As the adhesive energy does not depend on the droplet volume, this value can be used as an indicator to compare liquid samples of different volumes.
The sliding kit consisting of an external tilting stage and FAMAS software add-on is required to perform roll-off angle measurements.
Applications: Repellency/hydrophobicity, characterization of droplet hysteresis
Dynamic sliding method
The basic idea is the above-mentioned sliding method, but this method focuses on the roll-off speed and the roll-off acceleration of a droplet sliding off an inclined surface to observe hydrophobic and oleophobic properties in more detail.
Three-state method
The basic idea is the above-mentioned sliding method, but this method focuses on the roll-off speed and the roll-off acceleration of a droplet sliding off an inclined surface to observe hydrophobic and oleophobic properties in more detail.
Algorithms of contact angle analysis
The analysis software FAMAS offers the following different analysis algorithm methods that can be chosen to use the most appropriate method to determine the contact angle of a certain droplet in a certain condition (droplet size, droplet symmetry, contact angle range):
- Height-width method: Determines the contact angle from the height and diameter of the droplet's image.
- Circle fitting: Calculates a theoretical curve of a partial circle from the silhouette of the droplet
- Ellipse fitting: Calculates a theoretical curve of a partial ellipse from the silhouette of the droplet.
- Tangent method: Determines the tangent line using three endpoints close to each three-phase point of the droplet's image.
Surface free energy analysis of solids
The surface free energy of solids and their components are analyzed from the results of contact angle measurements with different chemicals. Different models to determine the surface free energy of solids, such as the geometric mean, the harmonic mean, acid-base, interaction analysis (work of adhesion, interfacial free energy), Young-Dupré, and the Zisman plot, are available.
The surface energy kit consisting of a set of needles and different chemicals is recommended for easy and quick analysis of the surface free energy.
Applications:
- Adhesive property
- Characterization of surface modification
- Digitalization of Hydrophilicity/hydrophobicity
Features:
- The standard deviation of contact angle measurements can be reflected in the standard deviation of surface free energy results.
- Imaginary numbers that may occur due to the analysis of hydrophobic surfaces can be eliminated by recalculation and subsequent adjustment. The residual value is then given as a reference.
Surface/interfacial tension of liquids
The pendant drop method enables the measurement of the surface and interfacial tension of liquids by using the algorithms of the Young-Laplace or the ds/de method. The pendant drop method has advantages in the following points compared to the conventional Wilhelmy plate and du Noüy ring method:
- Measurement of only a small amount of liquid (less than 1mL)
- High-temperature control (e.g., molten polymer applications)
- Due to short-term exposure to air, it is suitable for liquids that change surface tension quickly.
The pendant drop kit as an option is required.
Automatic recognition of droplet deposition
The deposition of a droplet from a needle onto a solid surface is recognized automatically by the analysis software, and a certain time interval between the deposition of the droplet and the start of the measurement can be set by the customer. This is especially convenient for liquid samples that rapidly spread on the solid surface, thus having a rapid initial change of the contact angles.
Focusing aid & droplet volume monitoring
- Focus level indicator: A bar chart and value are displayed on the live monitor and help to adjust the focus quickly and easily.
- Droplet volume display: The actual droplet volume is constantly being measured and displayed on the image monitor to help manual dispensing. When using an automatic dispenser, the droplet volume is automatically controlled by the software.
Display of data
Spreadsheet-like measurement sheets: Measurement results, as well as the average and standard deviation of each row data, are displayed in measurement sheets with 45x10 (RxC) cells.
- Variable data: Besides the contact angle, droplet volume, absorbing amount and ratio, droplet height, and droplet width are also being obtained.
- Charts: Different charts like contact angle against elapsed time can be drawn when measuring time function mode. The actual droplet volume is constantly measured and displayed on the live image monitor.
The droplet volume is software-controlled when using an automatic dispenser system.
Pixel calibration
The droplet calibration standard for the standard view is a basic accessory for all models. It is made of soda-lime glass bearing one full circle for calibration and three droplet silhouettes of 5°, 60°, and 108° for periodic inspections of measurement accuracy.
With the help of this tool, users can easily perform routine maintenance to ensure the reliability of their measurements over long periods.
A droplet calibration standard for calibration of the camera wide-view settings, as well as pendant drop calibration standards for standard and wide-view settings, can be obtained optionally. Certificates of accuracy of the full circle and the droplet silhouettes can also be obtained.
Other functions
- Movie converter: Converts the measurement images of time function to MPEG/AVI movie format.
- Threshold level adjustment: Helps to optimize the image analysis. Both the relative and absolute level adjustments are possible.
- Data correction on convex surfaces: The contact angles on convex surfaces, such as lenses and tubes in cross-section, can be corrected by simply entering the value of the substrate's radius or by actually measuring the curvature.