Paper Number
ET12 

Session
Advanced Experimental Techniques/Methods in Rheology

Title
Simultaneous slit rheology and structural characterization with small angle neutron scattering

Presentation Date and Time
October 15, 2018 (Monday) 4:35

Track / Room
Track 5 / San Felipe Room

Authors (Click on name to view author profile)

  1. Weigandt, Katie M. (NIST, Center for Neutron Research)
  2. Weston, Javen (University of Tulsa, Chemical Engineering)
  3. Hudson, Steven (NIST, Polymers and Complex Fluids Group)

Author and Affiliation Lines (in printed abstract book)
Katie M. Weigandt1, Javen Weston2, and Steven Hudson3
1Center for Neutron Research, NIST, Gaithersburg, MD 20899; 2Chemical Engineering, University of Tulsa, Tulsa, OK 74104; 3Polymers and Complex Fluids Group, NIST, Gaithersburg, MD 20899

Speaker / Presenter 
Weigandt, Katie M.

Text of Abstract
We are developing slit rheometers compatible with simultaneous small angle neutron scattering (SANS) measurements to directly correlate structure and rheology over a broad range of conditions. Eventually we hope to probe sample structure in Poiseuille flow at high shear rates, under high pressure head, and relatively high temperatures. This builds upon an existing suite of Couette rheoSANS and flowSANS devices at the NIST Center for Neutron Research that are accessible to the scientific community through a peer reviewed proposal system. Industrial applications, such as lubrication, mixing, spraying and injection, involve the flow of complex fluids at high deformation rates. Clogging, fluid degradation, and other processing challenges can arise in these extreme contexts and are often driven by structural changes in the fluid. To date, we have developed a prototype slit rheometer capable of simultaneously measuring structure and rheology of relatively low viscosity or shear thinning fluids (?8 < 5 mPa·s) at shear rates up to 100,000 s-1. Our initial investigations have focused on measuring wormlike micelle solutions at low to moderate shear rates and comparing the results with Couette rheoSANS measurements. In this talk we will discuss the ongoing development of µRheoSANS measurements including our existing low-pressure apparatus and our newly built high pressure µRheoSANS device, designed to withstand pressure drops or pressure heads up to 350 bar. This device will enable us to measure SANS at shear rates up to 106 in samples with ?8 ~ 100 mPa·s.