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Rheometers and Shear Cells

Instrument

Upgrades (completed)

Upgrades (in progress)

Capillary RheoSANS

  • Temperature control from 10 °C to 50 °C
  • Improved sample loading, priming, and air purging
  • Automated sample changing and cell rinsing
  • Rheometer control integration with NICE  

Rheometer MCR 301/501

  • New air-vacuum manifold to simplify equipment swap, beamline installation, sample changes and geometry alignment procedures
  • Rheometer control integration with NICE
  • Beam defining aperture setup

Rheometer ARES G2

  • New easy-access oven with insulated quartz windows
  • Improved maximum scattering angle enables measurements at higher q-values and in the 1-3 and 2-3 planes
  • Temperature control from -100 °C to 200 °C
  • Rheometer control integration with NICE
  • Improved gap insulation to further widen the operating temperature range
  • Time stamping complementary data streams, including impedance spectroscopy (Dielectric Rheo-SANS)

1-2 Shear Cell

  • New motor and controller allowing easier user interaction, better waveform definition and better integration with instrument control
  • Improved motor controls
  • New encoder feedback included within control loop
  • Rheometer control integration with NICE

 

Capillary RheoSANS
Originally developed with nSoft, Capillary RheoSANS (CRSANS) provides users access to shear rates up to 106 s-1, which is three orders of magnitude higher than shear rates achieved with a standard Couette cell rheometer [1].

CHRNS has upgraded this system by implementing temperature control from 10 °C to 50 °C, which includes all equipment and tubing in contact with the sample. CHRNS has also integrated high-pressure switch valves and flow selector valves, as well as a software-controlled procedure, to enable easier sample loading, system priming, and air purging.

rheometer and shear cells

Ongoing work aims to further improve sample handling by introducing automated cell rinsing and sample changing, as well as to integrate direct rheometer control and rheology data monitoring through the NICE control interface.

Rheometer MCR 301/501
The MCR 301 and 501 rheometers are commonly used instruments for RheoSANS, as they provide a large scattering volume and enable scattering measurements of the 1-3 shear planes (velocity-vorticity) and 2-3 shear planes (gradient-vorticity). These stress-controlled rheometers can measure properties across a broad range of shear rates from approximately 10-3 s-1 to 103 s-1 for most samples.

CHRNS has upgraded this system by implementing a new mounted air manifold with color coded connections and 3-way valves. These upgrades allow for faster and easier equipment swapping between measurements, for example, swapping from the Couette geometry to plate geometry. The new manifolds use a single quick disconnect and are identical for the MCR 301 and 501. This improvement facilitates faster rheometer installation on the beamline, and it enhances the user experience with more consistent and robust sample changes.

manifold and cables

Ongoing work aims to improve the alignment of the beam defining aperture, which would allow for more precise SANS measurements and lowered background. It would also significantly reduce the instrument alignment time, providing more time for experimental measurements. Additional work aims to fully integrate the MCR rheometers with the instrument control software suite. The full integration will allow users to fully control the rheometers from the NICE instrument software and to store all the rheological parameters with the SANS data file.

Rheometer ARES G2
The ARES G2 rheometer provides strain-controlled rheological measurements (meaning the strain input is decoupled from the stress output), which enables more advanced techniques such as orthogonal superposition rheometry. With the dielectric cell mounted, this rheometer can also be used to simultaneously measure the sample impedance spectroscopy, rheology, and SANS microstructure [2].

CHRNS has upgraded the forced-convection oven design to improve SANS measurements. The new oven design enables easier sample and geometry access while positioned on the neutron beamline, lowers background scattering by implementing double-paned quartz windows, and increases the maximum obtainable scattering angle. The forced-air convection design allows for fast temperature changes (approximately 1 °C/s) within the tested range from -100 °C to 200 °C.
 

shear cell

Ongoing work aims to further broaden the accessible temperature range by improving the oven insulation and gap seals. Improvements in the NICE software integration, time-stamping, and data visualization will facilitate on-the-fly data analysis of the simultaneous impedance, rheological, and SANS measurements.

1-2 Shear Cell
The 1-2 shear cell allows users to probe the microstructure of viscoelastic materials under the shear flow in the 1-2 plane (velocity-gradient), which is the flow plane that cannot be directly measured with other Couette-type geometries and rheometers. There is a strong coupling between the bulk rheology and microstructural features in the 1-2 plane of shear. For example, flow-instabilities such as shear banding can be studied by scanning the aperture across the gap in the 1-2 plane.

CHRNS has upgraded the motor and controller to provide better control of shear modes and a better interface for users. The new motor and controller also provide better integration with the SANS instrument.

instrument motor

Ongoing work aims to fully integrate this unique device with the instrument control software suite. It will allow to fully control the device from the instrument software which in term give us the capability to record all the device parameters and include them in the SANS data file.

References
[1] “Capillary RheoSANS: measuring the rheology and nanostructure of complex fluids at high shear rates”, Soft Matter, 16, 6285-6293, DOI: 10.1039/d0sm00941e (2020).
[2] “Dielectric RheoSANS — Simultaneous Interrogation of Impedance, Rheology and Small Angle Neutron Scattering of Complex Fluids”, J. Vis. Exp, 122, e55318, DOI: 10.3791/55318 (2017).
https://www.nist.gov/ncnr/sample-environment/sans-equipment/shear-and-rheology

MACS CHRNS
Created February 22, 2022