Surface tensiometers: measurement of surface & interfacial tension – Kyowa Interface Science Co. Ltd., Japan

Surface tension is a commonly used parameter to evaluate liquids and determine characteristics such as wettability, foamability, emulsifiability, solubility, and dispersibility. The surface tension of a liquid is its tendency to shrink into the minimum surface area possible. There are different surface tension measuring instruments available, employing a variety of measurement methods including:

  • Wilhelmy plate method
  • Du Noüy ring method
  • Pendant drop method
  • Bubble pressure method

Kyowa Interface Science Co. Ltd. is a Japanese manufacturer of technologically advanced instruments for measurement of surface and interfacial tension.
Using Kyowa surface tensiometers, you can evaluate liquids with parameters such as surface tension, interfacial tension, powder contact angle, and dynamic contact angle.

Surface tensiometer models

To cater to all possible fields of application, Kyowa offers different models with each one having certain specific features necessary for that application. The following is the line-up of Kyowa’s surface tension measurement instruments.

  • DY-300
  • DY-500 / DY-700

Measuring methods

surface tension (Wilhelmy plate and du Noüy ring method)
interfacial tension (Wilhelmy plate and du Noüy ring method)
lamella length (with use of the du Noüy ring)
liquid density 
sedimentation behavior 

Measuring range

surface/interfacial tension:1 to 1000mN/m





Calibration method

by external calibration weights

Sample stage operation:

software controlled
0.1 to 1.0mm/s

DY-500 & DY-700
Measuring methodssurface tension (Wilhelmy plate and du Noüy ring) interfacial tension (Wilhelmy plate and du Noüy ring) lamella length (du Noüy ring) liquid & solid density sedimentation behavior powder contact angle (Washburn method) dynamic contact angle
Measuring rangesurface/interfacial tension: 1 to 1000mN/m powder contact angle: 0-90° dynamic contact angle: 0-180°
Resolutionsurface/interfacial tension: 0.01mN/m powder contact angle: 0.01° dynamic contact angle: 0.01°
Accuracysurface/interfacial tension: 0.2mN/m contact angle: 0.2° surface/interfacial tension: 0.02mN/m contact angle: 0.02°
Calibration methodby an external calibration weight & by a built-in calibration system
Sample stage operation: Speed Strokesoftware controlled 0.002 to 50mm/s 50mm

Salient features of Kyowa surface tensiometers

Interfacial tension & surface tension measuring methods

The DY-300 gives values of surface tension, interfacial tension, lamella length, liquid density, and sedimentation behaviour. Using the more-advanced DY-500 and DY-700 models, additional parameters such as solid density, powder contact angle, and dynamic contact angle can be obtained. In Kyowa surface tensiometers, surface tension is measured by the Wilhelmy plate and Du Noüy ring methods. The main difference between the two methods is that in the former, the Du Noüy ring is pulled through the surface, while the Wilhelmy plate is kept stationary in the latter. Several ASTM standards approve the use of Du Noüy tensiometers. However, if the user wants to measure surface tension variations with time, Wilhelmy plate tensiometers are the only option. For applications such as measuring the time and end-point surface tension for formation of critical micelle concentration (CMC) of surfactants, Du Noüy tensiometers are not suitable. For versatility, Kyowa offers instruments using both methods for measurement of surface tension and interfacial tension. 

Temperature control units

In addition to the basic instrument, Kyowa surface tensiometers can be fitted with additional components. One of them is a temperature control unit which can simulate thermal process conditions for interfacial and surface tension measurement. Kyowa offers two types of temperature control units:

  • A jacket-type sample stage for temperature measurements from +10 to 70 deg C
  • A heater-type sample stage for temperature measurements from ambient to +150°C

The jacket-type temperature control unit is compatible only with the DY-300, while the heater-type one can be fitted with all the models.

Dynamic contact angle measurement

Similar to the temperature control units, DY-500 and DY-700 can also be fitted with an additional component for measuring dynamic contact angle. This would give a perspective on the contact angle hysteresis of the liquid being analysed. In Kyowa surface tensiometers, dynamic contact angle is measured by means of the Wilhelmy plate method. Using the advancing and receding contact angles, users can draw conclusions on chemical and topographical heterogeneity.

Bubble pressure tensiometer

Kyowa also manufactures fully automatic bubble pressure tensiometers that are widely used across the globe for dynamic surface tension measurement.
The BP-D5 assesses dynamic surface tension of a liquid by measuring the maximum internal pressure of a gas bubble formed in the liquid by means of a capillary. Bubble formation can be monitored with the pressure-voltage waveform displayed in real time and the images from the synchronized built-in stroboscope. With the real-time display of the waveform, users can monitor the condition on the lifetime and appropriately adjust the air flow rate.
This dynamic surface tension measuring instrument can measure values in the range of 10 to 100 mN/m with a resolution of 0.01 mN/m. Air supply can be controlled between 0.4 and 0.7 Mpa.
Bubble pressure tensiometers are used to determine specific parameters such as:

  • Concentration, lifetime, and dynamic surface tension of surfactants
  • Absorption rate of surfactants to control the dynamic surface tension
  • Forming time for micro-droplets in aerosols and emulsifiers
  • Concentration of cleaning or wetting agents in industrial baths
  • Dynamic surface tension and instant wettability of inks and coating fluids

Surface tensiometer applications

The different parameters obtained from surface tensiometers have diverse applications. Some of them are as follows:

Surface tension

  • Paints
  • Inks
  • Additives for coating

Interfacial tension

  • Transformer oils
  • Emulsions
  • Surfactant solutions

Lamella length

  • Paint leveling
  • Foaming stability of coatings
  • Foaming stability of fire extinguisher agents

Sedimentation behaviour

  • Flocculants in wastewater treatment
  • Stability of dispersions such as paints and pigmented inks

Surface tensiometer price

Agaram Industries is the exclusive distributor of surface tension measuring instruments manufactured by Kyowa Interface Science Co. Ltd. To get a quotation with the surface tensiometer price, you can fill up this form or directly send an email to

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