Force Tensiometer – K100

The universal instrument for analyzing surfactants and solid surfaces

Video | Universal analysis of liquid and solid surfaces

 

Our universal Force Tensiometer – K100 performs high-precision, automatic and reliable measurements of surface tension and interfacial tensioncritical micelle concentration CMC and contact angle on solids, fibers and powders. With high-quality components and a uniquely wide range of methods, the instrument carries out many tasks in the field of surfactant analysis and wettingmeasurement for your quality assurance or research. The simple changeover between different measuring methods takes place entirely without reconfiguring the instrument.

High-quality components for precise measurements

The principal measuring methods used by the K100 are based on the precise measurement of the force which occurs when wetting a measuring probe or a solid sample. We use a special force sensor with a particularly high resolution for the instrument in order to obtain reliable, accurate measurements, for example for determining surface and interfacial tension or contact angle. To ensure accurate measuring results, we use measuring probes such as rings and plates with highly accurate contours. This guarantees an exact correlation between measured force and the surface or interfacial tension.

The software-controllable sample stage moves in a wide speed range and communicates its exact position to the software with a resolution of 0.1 μm. This adds to the accuracy of results where position control is essential, e.g. for Du Noüy ring or contact angle measurements. The option of saving standard positions supports you in preparing the analyses.

An integral, automatic stirring function ensures optimum homogenization of dispersions before measuring or rapid equalization of concentration or temperature.

The ionizer inside the sample chamber ensures reliable contact angle measurements on solid samples and single fibers. The ionizer automatically removes the troublesome effect of static charge before the measurement is carried out. Otherwise, this could falsify the result in the form of an additional force.

As an addition to software control, the easy-to-use keypad for controlling the sample stage and other components such as the illumination or the stirrer, saves even more time. Thanks to the large sample chamber, the sample is loaded quickly, conveniently and safely into the instrument. Magnetically locking glass swing doors shield the sample chamber from troublesome air currents.

Many accessories expand the range of options

 

With different available temperature control units, measurements can be carried out between -15 and 300 °C: This  enables thermal process conditions to be simulated and even samples such as polymer melts or bitumen to be analyzed.

Our Micro Dispenser equips the Force Tensiometer – K100 for measuring the critical micelle concentration (CMC). The surfactant concentration range is set up and measured fully automatically. Working with two micro dispensers – one for dispensing the liquid and the other one to aspirate the same volume – enables a very wide concentration range. A high density of measuring points can be created in order to measure the CMC very accurately. Failed measurements due to an overly concentrated parent solution are virtually ruled out, as it can be diluted by several orders of magnitude to find the CMC.

We have also developed accurately shaped sample holders for exactly reproducible measurements with different types of sample for measuring the contact angle on powders and fiber bundles using the Washburn method. The density of liquids can also be accurately measured with a special solid measuring probe. This method is particularly useful when the density is required as an input parameter for other methods, for example when measuring surface tension using the ring method.

Other measuring probes and measuring options help you with the extensive characterization of solids or dispersions. These include measuring the density of solid substances, the sedimentation speed of dispersions and the penetration resistance of a sediment.

The K100, in the basic version K100C, is available with a slightly lower resolution force sensor and without the ionizer. The K100C is ideally suited to ensuring the quality of surfactant solutions by measuring the surface and interfacial tension.

Impressive instrument control and data management with our ADVANCE software

 

ADVANCE is our universal software designed to work with all KRÜSS instruments based on a common, intuitive approach. The relevant functions for each working step are arranged in tiles which display all elements necessary in the context. By avoiding the use of menus and pop-ups, ADVANCE saves any unnecessary clicks and time-consuming searches for hidden elements.

The K100 measuring methods run with pre-prepared templates that standardize the fully automated procedures down to the smallest detail, thus providing maximum repeatability. All raw data and results are clearly shown in several tiles that are custom-made for each method. Functions for comprehensive reports and data export as well as a fast access to result comparisons of up to 20 measurements make ADVANCE a powerful tool for managing and evaluating your data.

Tasks and applications

 

  • Determination of the effectiveness and efficiency of surfactants by CMC measurement
  • Wetting behavior of tablets, pharmaceutical active ingredients and excipients
  • Wetting of varnishes and paints
  • Decomposition product content in oils
  • Tank clearance and cleaning validation in the foodstuffs industry
  • Wetting and adhesion of coatings
  • Development of cosmetic products
  • Wetting properties of inks
  • Wetting of fiber bundles and textiles
  • Sedimentation and ductility of dispersions
  • Checking of surface modifications

Measuring methods and options

 

  • Surface tension and interfacial tension using the ring, plate and rod method
  • Surface tension and interfacial tension using the ring tear-off method, for example for measurements in accordance with ASTM D‑971
  • Critical micelle concentration (CMC) of surfactants
  • Contact angle and surface free energy of solids, powders or fiber bundles
  • Density of liquids and solids
  • Sedimentation behavior of dispersions
  • Penetration resistance of sediments
  • Measurement from -15 to 300 °C, temperature measurement with internal or external sensor

Force Tensiometer – K100SF

The high-precision tensiometer for measuring contact angle on single fibers

Our high-precision Force Tensiometer – K100SF is specially designed for analyzing the wettability of single fibers by measuring the contact angle. Our K100SF is fitted with a particularly high-resolution force sensor. The instrument therefore reliably measures the wetting forces on even very thin fibers, for example on single carbon fibers which are just a few microns thick.

Our K100SF has been specially developed for use in quality assurance and in the development of fiber coatings, particularly for the embedding of fibers in fiber reinforced materials. Good wettability of the fibers and good adhesion of the coatings are required in these applications. By measuring single fibers with our K100SF, quality assurance can be carried out at an early stage, namely before the fibers are made into bundles or matting. This enables early intervention in the case of quality deficiencies, resulting in less production waste and reduced cost.

Our Force Tensiometer – K100SF features various additional precision measuring methods. These include the measurement of surface tension and interfacial tension, the critical micelle concentration(CMC), the contact angle on powders and solids, and the measurement of liquid densities.

Tasks and applications

  • Characterization of natural and artificial fibers
  • Development of carbon and glass fiber coatings
  • Predicting the interaction between fibers and matrix
  • Optimization of hair care products

Measuring methods and options

  • Surface tension and interfacial tension using the ringplate and rod method
  • Surface tension and interfacial tension using the ring tear-off method, for example for measurements in accordance with ASTM D‑971
  • Critical micelle concentration (CMC) of surfactants
  • Contact angle and surface free energy of solids, powders or fiber bundles
  • Density of liquids
  • Measurement from -10 to 50°C, temperature measurement with internal or external sensor
  • K100SF accessories

    With the comprehensive range of accessories for our Force Tensiometer – K100SF, you can not only extend the scope of your instrument, but also adapt the measuring conditions exactly to suit your individual samples and requirements.

    Sample holders and preparation sets for contact angle measurement

    The accurate force sensor of the Force Tensiometer – K100SF measures the forces that occur as a result of the wetting of solids, which can be used to calculate the contact angle. Sample holders for contact angle measurements with different sample shapes and types transform your tensiometer into a reliable instrument for the analysis of solids.

     

    SH0601 – Sample holder for contact angle measurments on plate-shaped samples

    The SH0601 sample holder enables tensiometric measurements of the contact angle of plate-shaped solids using the Wilhelmy method. The sample holder is inserted into the tensiometer force sensor adapter in one quick step.

    The clip of the holder presses the sample against the pressing surface arranged exactly horizontally to the shaft, so that the sample is immersed in an exact vertical position during measurement. Whereby the sample is positioned on the horizontal upper edge of the pressing surface and thus straightly aligned.
     

    SH0602 – Sample holder for contact angle measurements on foils and films

    In order to carry out tensiometric measurements of the contact angle on foil and film samples using the Wilhelmy method, these samples are fixed firmly with the SH0602 special sample holder. The wide pressing surface of the clip that is arranged level with the shaft ensures the sample is firmly fixed and simplifies straight and vertical positioning of the sample during immersion in the test liquid.

    SH0801 – Sample holder for contact angle measurements on single fibers

    The SH0801 fiber holder makes preparation of single fiber contact angle measurements using the Wilhelmy method simple and reliable. The fiber is fixed to the reception surface of the stainless steel holder with the aid of double-sided adhesive foils.

    The matching SH0802 adhesive foils are available from us in sets of 50 foils.

    TO0910 – Enhanced single fiber holder and preparation set

    Our fiber holder and preparation set TO0910 simplifies the attachment and alignment of single fibers for precise contact angle measurements. The fiber holders in the set are plastic clips which fix the samples with the help of a UV-curing adhesive. At the same time, two V-shaped notches hold the fiber vertically. The clip is then quickly and accurately inserted in a special adapter for the tensiometer’s force sensor.

    The adhesive cartridge supplied has a very fine tip which enables the tiny amount required to be accurately applied. For easy handling, the cartridge rests in a holder which is fitted on the opposite side with a UV light source. The adhesive cures in only 10 seconds and the measurement can begin.
    The following components are included in the scope of supply:

    • Force sensor adapter
    • 1,000 plastic clips (available as spare parts SH0902)
    • Tube of adhesive, inserted in a holder with a fitted UV light source (available as spare parts TO0911)
    • Scalpel with five blades
    • Scissors
    • Tweezers

    SH0910 – Aluminum sample holder for contact angle measurements on powders and pigments

    We have developed the SH0910 aluminum sample holder for measuring the contact angle on powders and pigments using the Washburn method. The easy to clean sample tube with a perforated base is to be equipped with a filter paper base, filled with the sample and the holder, within seconds, hung in the respective force sensor adaptor. The matching filter paper SH0711 is available from us in sets of 100 filters.

    SH0912 – Glass sample holder for contact angle measurements on powders and pigments

    The SH0912 glass sample holder can be used as an alternative to the SH0910 aluminum sample holder for measuring the contact angle on powders and pigments using the Washburn method. The sample tube has a porous glass frit base and is quickly and simply equipped with a filter paper and filled with the sample. It is easy to check the height and evenness of the filling in the transparent tube.


    We recommend using the easy to clean SH0910 aluminum sample holder for severely soiling samples.

 

Measuring probes for analyzing liquids

There are a number of special probes available for your Force Tensiometer – K100SF, in addition to the standard probes for the Du Noüy ring method and the Wilhelmy plate method, for example for analyses using only small sample volumes.

 

PL0901 – Standard measuring probe for the Wilhelmy plate method

The PL0901 is our proven plate geometry for measuring the surface and interfacial tension using the Wilhelmy plate method. The dimensions of the plate comply exactly with the form specified in international standards and thus enable a high level of repeatability for the analyses. As the plate is made of the precious metal platinum it has an extremely high surface free energy and therefore also the required excellent wetting properties. These are further optimized by its homogenously roughened surface.

A simple clamping mechanism allows especially fast insertion of the plate. Its safe storage is assured through a high-quality protective box provided.

A PLC0901 version of the plate with a certificate from an independent testing institute is also available.

PL0902 – Wilhelmy plate measuring probe for small sample volumes

The PL0902 measuring probe enables measurement of the surface tension with the Wilhelmy plate method in the case of small sample volumes. It is the same size (wetted length) as our standard PL0901 plate and is also ideally wettable being made from the same precious metal platinum, but it is rolled cylindrically so it only requires a small surface area of the liquid. A high-quality protective box is provided for safe storage of the plate.

The scope of delivery of the rolled plate also includes a measuring vessel that can be used flexibly for different sample volumes: The hollow has a capacity of 5 mL and the vessel has concentric rings on its underside that can be filled with up to 1.2 mL or up to 0.2 mL.

PL0903 – Rod-shaped probe for measurements with the Wilhelmy method

The rod-shaped probe PL0903 can be used as an alternative to the rolled PL0902 for measuring the surface tension using the Wilhelmy method with small sample volumes. Thanks to its small diameter it is possible to carry out measurements in small vessels, but unlike the PL02 it also enables measurement of the interfacial tension. The rod is made of the ideally wettable precious metal platinum. A high-quality protective box is provided for its safe storage.

The scope of delivery of the rod also includes a measuring vessel that can be used flexibly for different sample volumes. The hollow has a capacity of 5 mL and the vessel has concentric rings on its underside that can be filled with up to 1.2 mL or up to 0.2 mL.

RI0901 – Standard measuring probe for the Du Noüy ring method

The RI0901 ring is our high-precision standard measuring probe for surface and interfacial tension using the Du Noüy ring method. The wire ring made of a platinum-iridium precious metal alloy is ideally wettable; the hardness of the iridium makes the measuring probe especially robust. The ring geometry is only connected to the shaft at two junctures, so that any disturbing influences on wetting are negligible.

A simple clamping mechanism allows especially fast insertion of the ring. Its safe storage is assured through a high-quality protective box provided.

An RIC0901 version of the ring with a certificate from an independent testing institute is also available.

RI0902 – Du Noüy ring measuring probe for small sample volumes

The special measuring probe RI0902 is used for measuring the surface tension with the ring method where only small sample volumes are available. Measurements with volumes as of 1 mL are possible thanks to the reduced diameter of the ring.

Like the standard RI0901 ring, the RI0902 is also made of a platinum-iridium alloy so its combines ideal wettability with the necessary metal hardness. Its design with only two contact points between the ring and the shaft and its shape accuracy ensure a high level of precision. A special vessel for small sample volumes is included in the scope of delivery as well as a high-quality protective box in which it can be safely stored.

Sample vessels and matching adapters

You can create the ideal conditions for the analysis of your special samples with the aid of a selection of sample vessels in various sizes and shapes and made of different materials.

 

Equipment for controlling temperature and gas atmosphere

A comprehensive range of accessories for carrying out measurements at defined temperature and gas atmosphere to accurately simulate the environmental conditions for your product or process or to carry out analyses of samples that are sensitive to oxygen.

 

TP0511/TP0512 – Temperature sensors for measurements with/without gas temperature controlled jacket

The TP0511 and TP0512 are highly accurate temperature sensors which can be used flexibly with your instrument. Thanks to the large measuring range at 0.1 °C precision, the sensors measures room temperature just as reliably as the working temperature of our accessories for temperature control. Measurement is carried out immediately at the sensor tip, thus reproducing the actual conditions directly at the solid or in the liquid sample. Our software links the temperature to the current analysis results.

Use of the sensor types:

  • TP0511 (top photo): Sensor set for the combination with a gas temperature controlled jacket TJ20
  • TP0512 (bottom photo): Sensor set for the standard setup of the tensiometer

TJ34 – Special thermostat jacket for large sample vessels

We have conceived the TJ34 thermostat jacket for temperature-controlled measurements of between -10 and 130 °C for large sample volumes. The jacket with its practical quick-lock connection accommodates the special SV30 sample vessel with its 98 mm outer diameter and is equipped with a powerful electromagnetic stirrer for effective thorough mixing of dispersions and viscous liquids. An integrated temperature sensor ensures continuous communication of the temperature inside the jacket.

Suitable thermostats are available from us.

TJ50 – Peltier temperature control unit from -15 to 130 °C

Our Peltier temperature control unit approaches the desired measuring temperature quickly and precisely. Next to measure­ments at high or low temperatures, the unit is especially suitable for analyses at accurately defined thermal standard conditions, which are hard to achieve with a simple liquid thermostat. Excellent insulation and an integrated stirrer provide for thermal stability and homogeneity.

Tools, aids and spare parts

To assist you when working with your instrument, we offer helpful accessories for preparing and carrying out your measurements.

 

PA0910 – Wind shield hood

Strong air streams can have a negative impact on the high-precision force sensor of your tensiometer even when the measurement chamber is closed. The complete measuring instrument fits under the PA0910 wind shield hood, which can be used in order to optimize the measurement of setups under a lab hood, for example.

SH0711 – Paper filters for Washburn powder contact angle measurements

The SH0711 paper filter set contains 100 filters used for carrying out powder contact angle measurements with the Washburn method. The round filters with a diameter of 8.15 mm fit into the SH0710, SH0910 and SH0912 special sample holders.

TO01 – Tool for adjusting distorted ring measuring probes

The delicate measuring probe for the Du Noüy ring method is easily bent if dropped or accidentally knocked rendering it unsuitable for the measurement. Our special TO01 tool can be used to restore the exact shape of the measuring element.

Alternatively our technical support also provides the re-alignment of deformed rings as a service or carries this out as part of the servicing of your instrument.