FAQ | Solution partner of measurements in interfacial chemistry: Kyowa Interface Science

The first thing to note is your solid sample size.
If your sample is bigger than any of our listed models, please contact us for a solution.
If you can prepare any size of samples, any model can be chosen. The next step is to see what options are available to meet your needs.
Temperature control and a sliding system are available for limited models.

Our Luer-lock needles have a two-digit number on their adapter section that indicates the needle gauge (indicated as G). The diameters of the stainless steel needles are:

* The external diameter of Teflon-coated needles are slightly larger since the thickness of the coating is about 20 to 30µm.

They are the same in the respect specifying an instrument in the field of surface science. There are varieties of Goniometers that play active roles in the fields for example physical therapy, crystallography, the spatial distribution of light, etc. Therefore, we are using the name “Contact Angle Meter” that name and natures agree.

Kyowa has local agents in several countries. Assistance with sales and technical support can be found on our website on the "Where to buy" page. Contact the local agent in your region. If there is no one available, contact us directly or through your local distributor of scientific instruments.

If you buy Kyowa's product through local agents listed on our webpage "Where to buy", they will provide technical support and parts with necessary instructions. For more details, please contact your local agents.
For customers who have purchased Kyowa's products directly from the company, we will support and provide necessary information directly through e-mails or phone calls. We provide services and support for at least seven years after purchase even if the product is discontinued.

A PDF file of the latest operation manual is available free of charge. If you are a user of the software FAMAS or DYNALYZER, please proceed to your user registration at "Registration" and obtain the access keys necessary to enter the download site, where PDF files of the operation manual and the latest version of the software are available.
If you are not a user of the above software, contact us or our agents found at "Where to buy". Give us the model and the serial number of your product.
Operation manuals for some older products may no longer be available. Hard copies of operation manuals are provided for value.

Larger droplets tend to be rather flattened due to gravity's effect. This may cause errors of measurement. On the other hand, smaller droplets may be difficult to measure due to quick evaporation. In general, a droplet volume of around 1 to 2 µL is used.

For example, JIS R3257 “Testing method of wettability of glass substrate” indicates “1µL or larger, 4µL or smaller”. ASTM D5946 “Corona-treated polymer films using water contact angle measurements” indicates 5 - 8µL”. In our opinion, these volumes are rather larger.

We recommend replacing the liquid sample every day to avoid problems caused by accidental contamination or deterioration of the liquid.

An ultrasonic cleaner with solvents or surfactant solutions is recommended.

Syringes used for oily samples are better handled under a separate process than for cleaning syringes used for water-soluble samples.

The major objective of contact angle measurements is to evaluate combinations of liquid and solid. Another objective is to compare solids using a liquid as standard. In the later objective, water is the liquid most commonly used.
Purified water such as DI water, distilled water, and pure water is recommended. City tap water is not recommended because it may include some elements that will negatively affect the results.
In addition, the papers for surface free energy analysis stipulate typical probe liquids for analysis. Those include diiodomethane, formamide, ethylene glycol, and so on as well as water.

A sessile drop calibration standard bearing one full circle for calibration and three droplet silhouettes of
5°, 60°, and 108° for periodic inspections of measurement accuracy is provided with any Kyowa contact angle meter.

Surface tensiometers are classified within the following three categories:
1. Force tensiometers (DyneMaster series)
Depending on the grade of the model, the built-in electric balances can be calibrated using the provided calibration weight(s) or the internal automatic calibration system. Inspection can be performed with a liquid of pure substance of which surface tension is published. Purified water and ethanol are recommended.
2. Dynamic tensiometers (bubble pressure tensiometers)
Calibration is carried out using purified water.
3. Optical Tensiometers (DropMaster series using the pendant drop method)
Pendant drop calibration standards bearing one full circle for calibration and pendant drop silhouettes for periodic inspections of measurement accuracy are available.

Kyowa recommends the Wilhelmy Plate method rather than the du Noüy Ring method for measuring surface tension because of the following advantages of the Wilhelmy Plate method:

• Variations over time can be measured, which is essential for solutions including surfactants that lower the surface tension.
• The plate's shape is simple and comparatively durable whereas the ring's shape is complex and needs very careful handling so as not to bend its thin and soft wires. A change of the ring's diameter and circularity make a big difference in measurement results.
• A correction by liquid density is not required if the density is within 0.6 – 1.4 g/cm3. Using the du Noüy Ring method the liquid's density parameter must be set prior to measurements.

However, Kyowa respects the du Noüy Ring method for its long history and extra function in measuring Lamella length. In response to the demand for only the du Noüy Ring, it is possible to obtain a du Noüy Ring and a Ring reformer instead of two Wilhelmy plates as a standard accessory for the DyneMaster series.