Australian Research Council Centre of Excellence in Plant Cell Walls, The University of Queensland, Brisbane, Qld 4072, Australia; School of Chemical Engineering, The University of Queensland, Brisbane, Qld 4072, Australia.
Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld 4072, Australia; Key Laboratory of Chemical and Biological Transformation Processes, School of Chemistry and Chemical Engineering, Guangxi University for Nationalities, Nanning 530006, China.
Carbohydr Polym. 2015 Nov 20;133:507-16. doi: 10.1016/j.carbpol.2015.06.087. Epub 2015 Jul 9.
Soluble starch polymers are shown to enhance the lubrication of ionic liquid-water solvent mixtures in low-pressure tribological contacts between hydrophobic substrates. A fraction of starch polymers become highly soluble in 1-ethyl-3-methylimidazolium acetate (EMIMAc)-water solvents with ionic liquid fraction ≥60wt%. In 65wt% EMIMAc, a small amount of soluble starch (0.33wt%) reduces the boundary friction coefficient by up to a third in comparison to that of the solvent. This low-friction is associated with a nanometre thick film (ca. 2nm) formed from the amylose fraction of the starch. In addition, under conditions where there is a mixture of insoluble starch particles and solubilised starch polymers, it is found that the presence of dissolved amylose enhances the lubrication of starch suspensions between roughened substrates. These findings open up the possibility of utilising starch biopolymers, as well as other hydrocolloids, for enhancing the performance of ionic liquid lubricants.
可溶性淀粉聚合物被证明可以增强疏水性基底在低压摩擦学接触中离子液体-水溶剂混合物的润滑性能。在离子液体分数≥60wt%的 1-乙基-3-甲基咪唑醋酸盐（EMIMAc）-水溶剂中，部分淀粉聚合物变得高度可溶。在 65wt%的 EMIMAc 中，少量的可溶性淀粉（0.33wt%）与溶剂相比，将边界摩擦系数降低了三分之一。这种低摩擦与由淀粉的直链淀粉部分形成的纳米厚膜（约 2nm）有关。此外，在存在不溶性淀粉颗粒和可溶性淀粉聚合物混合物的情况下，发现溶解的直链淀粉的存在增强了在粗糙基底之间的淀粉悬浮液的润滑。这些发现为利用淀粉生物聚合物以及其他水胶体来增强离子液体润滑剂的性能开辟了可能性。
