What you can measure

  • Critical Micelle Concentration
    Du Noüy ring and Wilhelmy plate methods
  • Surface tension
    Du Noüy ring and Wilhelmy plate methods
  • Interfacial tension
    Du Noüy ring and Wilhelmy plate methods
  • Dynamic contact angle
    Wilhelmy methods 
  • Surface free energy
    Based on contact angle measurements
  • Powder wettability
    Washburn method
  • Density
    Density probe
  • Sedimentation
    Sedimentation probe
  • Adhesion force
    Liquid droplet pull-off method

Widen you view

In this 1-minute video, you will get a quick view of Sigma CMC. For the best experience, watch it in fullscreen mode!

3 reasons to invest

Full CMC automation for high precision

Everything from measuring surface tension and changing surfactant solution concentration to analyzing the shape of the CMC curve automatically ensures a user-independent and unattended operation. Integrated magnetic stirrer ensures surfactant solution homogeneity.


Sophisticated software

The OneAttension software provides full versatility and automation, easy measurement setup, and live results. But above all, it is really user-friendly and intuitive. Includes features like autosearch to reduce CMC measurement time by automatically increasing the number of data points only around the CMC point.


Optimized yet versatile

Sigma CMC is an adaptable and versatile system that not only measures CMC but also has the full support of other surface measurement modes from surface tension to powder wettability. This ensures the system is future-proof for any measurement needs that may come to you.

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A closer look

Sigma CMC is based on the versatile Sigma 701 that is known for its particularly high sensitivity. It can also be used with the Sigma 700 which is optimized for powder wettability and contact angle measurements. Check out the system specifications below.

Sigma 700
Sigma 701

Available Measurements 

Surface tension

      √        √

Interfacial tension

       √        √

Critical Micelle Concentration

 Automatic  Automatic

Dynamic contact angle

       √        √

Surface free energy

       √        √

Powder wettability

       √        √


       √        √


       √        √

Balance Specifications 

Measuring range (mN/m)

1…2000 1…2000

Displayed resolution (mN/m)

0.001 0.001

Density range (g/cm3)

0…2.2 0…2.2

Density resolution (g/cm3)

0.0001 0.0001

Maximum load (g)

210 5

Weighing resolution (mg)

0.01 0.005

Force resolution (µN)

0.1 0.05

Contact angle range (°)

0…180 0…180

Contact angle resolution (°)

0.01 0.01

Calibration & Locking

Automatic Manual

Measuring Unit Specifications    

Sample stage

Motorized Motorized

Sample stage speed (mm/min)

0.01…500 0.01…500

Stage positioning resolution (µm)

0.016 0.016

Dimensions (L×W×H, cm)

33.3×24.4×62 33.3×24.4×62

Weight (kg)

16.3 13

Power supply (VAC)

85…264 85…264

Power consumption (W)

13 13

Frequency (Hz)

47…440 47…440

Common Accessories

Temperature control range (° C)

-20…+200 -20…+200


       √        √


Provided software

OneAttension OneAttension

System Requirements 

Recommended system requirements

  • 1 GHz processor
  • 1 GB RAM
  • 40 GB hard disk drive (20 GB free)
  • 1 USB-port
  • Accessories such as water bath and liquid dispenser may require a free USB port

Operating system requirements

  • Windows 7 & 8 &10 (32 or 64 bit)
  • Windows Vista (32 bit)


OneAttension Software

OneAttension software is a fine combination of a very intuitive interface and high functionality. Follow your experiment live and get the results within seconds. Let's have a look at the features! 



OneAttension Features

  • Full automation
    OneAttension supports fully automated measurements - get CMC values with a click of a button
  • Live analysis
    The results are shown in real-time during the measurement. You can conveniently monitor your results as they are forming
  • Best in class interface
    The software is easy to learn, and the logical interface allows even complex measurements to be performed with ease
  • Flexibility for every need
    OneAttension has been designed to meet the requirements of almost any applications you may have. You can easily adjust measurement parameters to match your specific application needs
  • Data handling and exporting made simple
    Data analysis, plotting, and statistical analysis can all be done with a few clicks to give you accurate results within seconds. All data can easily be exported further to Excel, for example
  • Optimal for industrial use
    Measurement reports can be created with a few clicks and the user manager conveniently handles all different users – with desired privacy levels. Autosearch function saves measurement time


Add more possibilities

Have a look at a few of the accessories that can be used for added capabilities. You can find the full range below in the accessory brochure. 


Platinum Du Nouy ring

Pt-Ir-ring made to fulfill the requirements at least in following standards; ISO 301, ISO 4311, ISO 6889, ASTM D1331 and ASTM D 971. Includes also additional weight for push-mode.


Platinum Wilhelmy plate

Platinum Wilhelmy plate with micro roughened surface.


Thermostatic vessel (from -20 to +200°C)

For temperature control of the sample liquid. A heat exchange vessel with fluid jacket type of construction. 


Temperature probe

PT-100 temperature measurement probe with holder. The temperature is shown in OneAttension software. 


What others say

Our instruments are present at many prestigious universities and research facilities world wide. Take a minute to find out what others say about Sigma instruments. 



Researcher at Riken

"We wanted the most accurate force tensiometer on the market for our research on surface tension. Our in-depth testing of the Attension force tensiometer convinced us: it is the one."


Riken, Japan

Riken is a Japanese research institute established in 1917. Its research areas include physics, chemistry, biology, medical science, engineering and computational science.


Learn more

We have gathered all our in-depth knowledge associated with Sigma 700/701. Browse around amongst webinars, overviews and white papers to find a topic of interest. 

  • Attension

The Importance of Contact Angle in Industry

Get examples of how contact angle measurements are utilized in different industries.

Get it
  • Attension
White Paper

Surface and Interfacial Tension

Learn what it is and read our review of the most commonly used measurement techniques.

  • Attension

Surface Free Energy Methods

You get an introduction to surface free energy methods and a comparison chart.

Get it
  • Attension

The Importance of Surface Tension in Industry

Detergents, paints, food. We give you examples to how surface and interfacial tension measurements are utilized in different industries.

Get it
  • Attension
White Paper

Contact Angle - What is it and how do you measure it?

Learn more about one of the most used measurement method to study the wettability of the surface.

  • Attension
White Paper

Surface Free Energy - What is it and how to measure it?

We explain the concept of surface free energy and present the most important theories behind it.

  • Attension

Surface Free Energy in Practice

We give you the reasons why to measure surface free energy and show how it is done.

Go there
  • Attension
White Paper

Surface and Interfacial Tension

Study the different measurement methods to select the best choice for your application.

  • Attension

Surface Tension and Surfactants in Industrial Processes

Get an overview of how surfactants are used in industrial processes.

Go there
  • Attension

Using Contact Angle Measurements in Surface Research and Quality Control

Get an understanding about how contact angle measurements are utilized in industry to optimize and control surfaces.

Go there
  • Attension
White Paper

Wettability Measurements in Biomedical Applications

Read how wettability measurements have been utilized in biomedical research

  • Attension

Critical Micelle Concentration - What is it and how to measure it?

Learn more about critical micelle concentration and how it can be measured with surface tension measurements

Get it
  • Attension

Powder Wettability

Explains two most common ways to measure wettability of powders.

Get it
  • Attension

Powder Wettability - How to Measure Contact Angle of Powders

We review some of the most commonly used methods and their suitability for different applications.

Go there