TY  - JOUR
AU  - Lang, Christian
AU  - Kohlbrecher, Joachim
AU  - Porcar, Lionel
AU  - Lettinga, M.P.
TI  - The Connection between Biaxial Orientation and Shear Thinning for Quasi-Ideal Rods
JO  - Polymers
VL  - 8
IS  - 8
SN  - 2073-4360
CY  - Basel
PB  - MDPI
M1  - FZJ-2016-05169
SP  - 291
PY  - 2016
AB  - The complete orientational ordering tensor of quasi-ideal colloidal rods is obtainedas a function of shear rate by performing rheo-SANS (rheology with small angle neutronscattering) measurements on isotropic fd-virus suspensions in the two relevant scatteringplanes, the flow-gradient (1-2) and the flow-vorticity (1-3) plane. Microscopic ordering canbe identified as the origin of the observed shear thinning. A qualitative description of therheological response by Smoluchowski, as well as Doi–Edwards–Kuzuu theory is possible,as we obtain a master curve for different concentrations, scaling the shear rate with theapparent collective rotational diffusion coefficient. However, the observation suggests that theinterdependence of ordering and shear thinning at small shear rates is stronger than predicted.The extracted zero-shear viscosity matches the concentration dependence of the self-diffusion ofrods in semi-dilute solutions, while the director tilts close towards the flow direction already atvery low shear rates. In contrast, we observe a smaller dependence on the shear rate in the overallordering at high shear rates, as well as an ever-increasing biaxiality.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000384520900007
DO  - DOI:10.3390/polym8080291
UR  - https://juser.fz-juelich.de/record/819526
ER  -