Rheometers and Shear cells
Strain controlled rheometer:
TA Instruments ARES with sealed bath.
20 g.cm and 1000 g.cm maximum torque, with automatic switching.
Couette Double wall (Bob R1=14.75 mm, Bob R2=16 mm, Cup R1= 13.975, Cup R2= 17.00)
Couette Single wall (Bob R= 17 mm, Cup R=16 mm)
Couette Single wall (Bob R= 8.5 mm, Cup R=8.25 mm)
Shear cell for Confocal Microscopy
High-speed microscopy in zero-velocity plane
We have a set-up where we can perform microscopy in the zero-velocity plane, due tto the fact that we can independently move the cone and the plate. The plate is made from 0.17 mm glass such that we can use high NA emersion objectives (up to NA=1.4). In the detection line we can either use a fast scanning confocal microscope ( VTinfinity with a maximum frequency of 360 frames per seconds, depending on the camera) or bright field (fluorescence). The available detection cameras are: Roper CoolSnap HQ, Roper cascade1K, and the Hamamatsu C9100.
( P. Lettinga )
Shear cell for Neutron Scattering
( P. Lettinga )
Shear cell for Light Scattering
Small and Wide Angle Light Scattering under shear
The setup allows (time resolved) Light Scattering measurements under shear from a transparent Couette cell with rotating inner cylinder (see Available Shear Cells). We make use of a prism placed within the inner cylinder to send the light through the gradient direction of one single gap, thus probing the flow vorticity plane. The scattered light is projected on a screen, and a CCD camera (Micromax, Rooper Scientific) is used for data collection. Labview-based software is used to control both the shear rate and the camera, which allows for time-resolved measurements. We can use light sources with wavelengths of 440 nm, 532 nm, and 632 nm, so we can probe structures between 250 nm and several microns in two dimsensions, and even smaller structures in one dimension.
Omitting the thermo-stating chamber and using cells with a flattened surface we can use the set-up also in combination with a microscope to perform microscopy under shear. Also the use of polarizers is optional as well as macroscopic birefringence measurements on the whole cell.
( P. Lettinga, H. Kriegs )