Capillary RheoSANS: measuring the rheology and nanostructure of complex fluids at high shear rates

Soft Matter ◽  
2020 ◽  
Vol 16 (27) ◽  
pp. 6285-6293
Author(s):  
Ryan P. Murphy ◽  
Zachary W. Riedel ◽  
Marshall A. Nakatani ◽  
Paul F. Salipante ◽  
Javen S. Weston ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Complex Fluids ◽  
Inorganic Nanoparticles ◽  
High Shear ◽  
Capillary Rheometry ◽  
Shear Rates ◽  
High Shear Rates

Capillary rheometry is combined with small-angle neutron scattering to simultaneously measure the viscosity and nanostructure of complex fluids containing proteins, surfactants, polymers, and inorganic nanoparticles at shear rates up to 106 s−1.

Shear Induced Phase Behavior of Polymer Blends by Small Angle Neutron Scattering

1989 ◽  
Vol 166 ◽  
Author(s):  
Alan I. Nakatani ◽  
Hongdoo Kim ◽  
Charles C. Han
Keyword(s):  
Neutron Scattering ◽  
Polymer Blends ◽  
Phase Behavior ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Large Body ◽  
Concentric Cylinder ◽  
Shear Rates ◽  
Lower Shear ◽  
High Shear Rates

ABSTRACTThe phase behavior of polymer blends and solutions can be changed dramatically by a flow field using a variety of flow geometries. Unlike simple binary fluids which require extremely high shear rates to produce only small shifts in the phase boundary, polymer phase behavior may be influenced by as much as 10 degrees with the application of much lower shear rates. However, there is a large body of conflicting data concerning the nature of these shear effects in polymers.Here we report on the effects of shear on the phase behavior of polymer blends by small angle neutron scattering (SANS). Experiments were conducted using a specially constructed, concentric cylinder apparatus for in situ studies of concentrated polymer solutions and melts. Two separate systems will be discussed: 1) a blend of polystyrene and polybutadiene. 2) a blend of polystyrene and poly(vinylmethylether). Both systems exhibit shifts in the phase behavior which indicate shear induced mixing in agreement with previous results obtained by other techniques. These results will be interpreted within the context of existing theories of shear induced phase behavior.

Small-angle neutron scattering study of shear-induced phase separation in aqueous poly(N-isopropylacrylamide) solutions

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Markus Stieger ◽  
Peter Lindner ◽  
Walter Richtering
Keyword(s):  
Phase Separation ◽  
Shear Flow ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Separation Process ◽  
High Shear ◽  
Shear Rates ◽  
High Shear Rates ◽  
Strong Shear ◽  
Phase Separation Process

Abstract The influence of shear flow on the structure of concentrated aqueous poly(N-isopropylacrylamide) solutions near the lower critical solution temperature was investigated by means of small-angle neutron scattering. Two samples, both in the semi-dilute regime above the overlap concentration, were studied. The scattering curve of the less concentrated sample was not influenced by shear flow, although high shear rates were reached. The more concentrated 4 wt.-% sample, however, displayed shear-induced demixing under strong shear flow conditions. Experiments at different shear stresses indicated the existence of a threshold shear stress and the phase separation process became faster with increasing stress. The two-dimensional scattering patterns remained isotropic even during the phase separation process and the correlation length as obtained from an Ornstein- Zernike plot increased. The influence of shear flow on the phase separation process is thus similar to a temperature increase. The results are in excellent agreement with data from recent rheo-optical experiments where shear-induced phase separation was also observed for the concentrated solution at high shear rates. Apparently, strong shear flow exerts an effect analogous to a temperature increase.

scholarly journals A small-angle neutron scattering investigation of rigid polyelectrolytes under shear

2003 ◽  
Vol 36 (4) ◽  
pp. 1000-1005 ◽  
Author(s):  
E. Mendes ◽  
S. Viale ◽  
O. Santin ◽  
M. Heinrich ◽  
S. J. Picken
Keyword(s):  
Neutron Scattering ◽  
Cross Sections ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Deuterated Water ◽  
Shear Rates ◽  
Scattering Spectrum ◽  
High Shear Rates ◽  
Low Concentrations ◽  
Small Shear

Solutions of a rigid polyelectrolyte molecule, sulfo-poly(phenyleneterephthalamide) (SPTTA), in deuterated water have been investigated using small-angle neutron scattering. At low concentrations (1 wt%) the scattering spectrum presents a soft maximum similar to that of the interaction of rod-like objects. Two counterions are used, H+and Li+, and it is shown that aggregation is favoured as the proportion of Li+counterions increases. When kept at rest at room temperature, the solutions exhibit spontaneous birefringence. A 1 wt% solution was investigated under shear and it is shown that a very small shear rate is needed to produce a very strong alignment of rod-like objects. Such alignment saturates at high shear rates. Upon cessation of shear, a very long relaxation time is observed. The set of results strongly suggest aggregation of rigid polyelectrolyte molecules into long needles exhibiting very small cross sections.

scholarly journals Studying solutions at high shear rates: a dedicated microfluidics setup

2016 ◽  
Vol 23 (2) ◽  
pp. 480-486 ◽  
Author(s):  
D. C. F. Wieland ◽  
V. M. Garamus ◽  
T. Zander ◽  
C. Krywka ◽  
M. Wang ◽  
...  
Keyword(s):  
Shear Rate ◽  
Small Angle ◽  
Protein Solutions ◽  
High Shear ◽  
X Ray ◽  
Shear Rates ◽  
X Ray Scattering ◽  
High Shear Rates ◽  
Shear Gradient ◽  
Ray Scattering

The development of a dedicated small-angle X-ray scattering setup for the investigation of complex fluids at different controlled shear conditions is reported. The setup utilizes a microfluidics chip with a narrowing channel. As a consequence, a shear gradient is generated within the channel and the effect of shear rate on structure and interactions is mapped spatially. In a first experiment small-angle X-ray scattering is utilized to investigate highly concentrated protein solutions up to a shear rate of 300000 s−1. These data demonstrate that equilibrium clusters of lysozyme are destabilized at high shear rates.

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