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Characterizing Single-Molecule Conformational Changes Under Shear Flow with Fluorescence Microscopy
Published on: January 25, 2020
Xylan Conformation and Dispersion Govern Shear-Thickening Fluid Rheology
Hefeng Shen1,2, Yuanting Dai1,2, Xiang Hao1,2
1Beijing Key Laboratory of Lignocellulosic Chemistry, MOE Engineering Research Center of Forestry Biomass Materials and Bioenergy, Beijing Forestry University, Beijing 100083, China.
Abstract:
The microscopic state of polysaccharides in solution─whether dissolved, dispersed, or aggregated─directly dictates the macroscopic properties of the bulk fluid. However, the influence of their true state in solution and nanostructures on rheology is often overlooked. Here, using non-Newtonian shear-thickening fluids (STFs, SiO2/poly(ethylene oxide)) as a model, we systematically investigate how xylan conformation and dispersion affect STFs' rheology. Xylan nanocrystals (XNCs) and water-soluble xylan ethers with distinct dispersibility (well-dispersed vs aggregate) and solubility (room-temperature-soluble vs high-temperature-soluble) are synthesized. Among those, well-dispersed XNCs and room-temperature-soluble xylan ethers exhibit a pronounced thickening effect in STFs, reducing the critical shear rate by 2 orders of magnitude and increasing peak viscosity by 880%. This work demonstrates that polysaccharide conformation and dispersion behavior exert pronounced effects on STF rheology, providing a new avenue for leveraging polysaccharides as fluid additives.
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