TY - JOUR
T1 - Propagation of Orientation Across Lengthscales in Sheared Self-Assembling Hierarchical Suspensions via Rheo-PLI-SAXS
AU - Ghanbari, Reza
AU - Terry, Ann
AU - Wojno, Sylwia
AU - Bek, Marko
AU - Sekar, Kesavan
AU - Sonker, Amit Kumar
AU - Nygård, Kim
AU - Ghai, Viney
AU - Bianco, Simona
AU - Liebi, Marianne
AU - Matic, Aleksandar
AU - Westman, Gunnar
AU - Nypelö, Tiina
AU - Kádár, Roland
N1 - Publisher Copyright:
© 2024 The Author(s). Advanced Science published by Wiley-VCH GmbH.
PY - 2024/12/25
Y1 - 2024/12/25
N2 - Simultaneous rheological, polarized light imaging, and small-angle X-ray scattering experiments (Rheo-PLI-SAXS) are developed, thereby providing unprecedented level of insight into the multiscale orientation of hierarchical systems in simple shear. Notably, it is observed that mesoscale alignment in the flow direction does not develop simultaneously across nano-micro lengthscales in sheared suspensions of rod-like chiral-nematic (meso) phase forming cellulose nanocrystals. Rather, with increasing shear rate, orientation is observed first at mesoscale and then extends to the nanoscale, with influencing factors being the aggregation state of the hierarchy and concentration. In biphasic systems, where an isotropic phase co-exists with self-assembled liquid crystalline mesophase domains, the onset of mesodomain alignment towards the flow direction can occur at shear rates nearing one decade before a progressive increase in preferential orientation at nanoscale is detected. If physical confinement prevents the full formation of a cholesteric phase, mesoscale orientation occurs in shear rate ranges that correspond to de-structuring at nanoscale. Interestingly, nano- and mesoscale orientations appear to converge only for biphasic suspensions with primary nanoparticles predominantly made up of individual crystallites and in a high-aspect ratio nematic-forming thin-wall nanotube system. The nano-micro orientation propagation is attributed to differences in the elongation and breakage of mesophase domains.
AB - Simultaneous rheological, polarized light imaging, and small-angle X-ray scattering experiments (Rheo-PLI-SAXS) are developed, thereby providing unprecedented level of insight into the multiscale orientation of hierarchical systems in simple shear. Notably, it is observed that mesoscale alignment in the flow direction does not develop simultaneously across nano-micro lengthscales in sheared suspensions of rod-like chiral-nematic (meso) phase forming cellulose nanocrystals. Rather, with increasing shear rate, orientation is observed first at mesoscale and then extends to the nanoscale, with influencing factors being the aggregation state of the hierarchy and concentration. In biphasic systems, where an isotropic phase co-exists with self-assembled liquid crystalline mesophase domains, the onset of mesodomain alignment towards the flow direction can occur at shear rates nearing one decade before a progressive increase in preferential orientation at nanoscale is detected. If physical confinement prevents the full formation of a cholesteric phase, mesoscale orientation occurs in shear rate ranges that correspond to de-structuring at nanoscale. Interestingly, nano- and mesoscale orientations appear to converge only for biphasic suspensions with primary nanoparticles predominantly made up of individual crystallites and in a high-aspect ratio nematic-forming thin-wall nanotube system. The nano-micro orientation propagation is attributed to differences in the elongation and breakage of mesophase domains.
KW - advanced rheological techniques
KW - cellulose nanocrystals
KW - liquid crystalline suspensions
KW - multiscale orientation
KW - polarized light imaging
KW - small-angle X-ray scattering
UR - http://www.scopus.com/inward/record.url?scp=85212933633&partnerID=8YFLogxK
U2 - 10.1002/advs.202410920
DO - 10.1002/advs.202410920
M3 - Article
AN - SCOPUS:85212933633
SN - 2198-3844
JO - Advanced Science
JF - Advanced Science
M1 - 2410920
ER -