Accessory for MCR:
Electrorheological Device

Application of an electric field during rheological measurement

The MCR rheometer series characterizes ERFs in an infinitely variable electric field up to 12,500 volts DC (direct current, 25,000 volts peak to peak, max. current 1 mA). AC (alternating current) is also available as an option. The voltage is applied to the shaft of the measuring system and the electric circuit closes as soon as the measuring system (plate or cup) is connected. Both measuring systems – parallel plate (up to 50 mm) and concentric cylinder geometries (up to 27 mm) – can be combined with different kinds of temperature devices (Peltier, electrical, convection) to apply a temperature range between -50 °C and +300 °C. Even lower temperatures are available on request.

Maximum-safety measurement control

A certified, integrated safety concept ensures convenient and safe handling. As soon as the safety hood or the oven is opened, the current stops. All rheological test types can be performed while the electric field is applied – even sensitive measurements in oscillation. The rheometer’s RheoCompass software controls and monitors the electric field and rheological parameters. Individual measuring procedures can be defined, or predefined test templates used. The software also enables post-measurement data processing and inclusion into reports.

Investigations of ERFs

The Electrorheological Device is especially designed for investigations of ERFs – suspensions of very fine electrically active particles (up to 50 micrometers diameter) in an electrically insulating fluid. These kinds of fluids need to be characterized due to their unique "smart" rheological properties, which change when an electrical field is applied. However, the device can also be used to investigate any materials that change their flow properties under the influence of an electric field. Typical examples include:

• Haptic devices (e.g., for remote-controlled surgery)
• Touch panels for computers (e.g., Braille letters for visually impaired users)
• Clutches, brakes, pumps, dampers, shock absorbers
• Crude oil (e.g., to influence pumpability)
• Printing inks
• Food products (e.g., chocolate, starch suspensions)