Li Hua, Zhang Yunxiao, Jones Seamus, Segalman Rachel, Warr Gregory G, Atkin Rob
School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia; Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia, Australia.
School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia.
J Colloid Interface Sci. 2022 Jan 15;606(Pt 2):1170-1178. doi: 10.1016/j.jcis.2021.08.067. Epub 2021 Aug 16.
The polymeric cations of polymeric ionic liquids (PILs) can adsorb from the bulk of a conventional ionic liquid (IL) to the Au(111) electrode interface and form a boundary layer. The interfacial properties of the PIL boundary layer may be tuned by potential.
Atomic force microscopy has been used to investigate the changes of surface morphology, normal and lateral forces of a 5 wt% PIL/IL mixture as a function of potential.
Polymeric cations adsorb strongly to Au(111) and form a polymeric cation-enriched boundary layer at -1.0 V. This boundary layer binds less strongly to the surface at open circuit potential (OCP) and weakly at + 1.0 V. The polymeric cation chains are compressed at -1.0 V and OCP owing to electrical attractions with the electrode surface, but fully stretched at + 1.0 V due to electrical repulsions. The lateral forces of the 5 wt% PIL/IL mixture at -1.0 V and OCP are higher than at + 1.0 V as the polymeric cation-enriched boundary layer is rougher and has stronger interactions with the AFM probe; at + 1.0 V, the lateral force is low and comparable to pure conventional IL due to displacement of polymeric cations with conventional anions in the boundary layer.
聚合离子液体（PILs）的聚合阳离子可从常规离子液体（IL）本体吸附至Au(111)电极界面并形成边界层。PIL边界层的界面性质可通过电位进行调节。
已使用原子力显微镜研究5 wt% PIL/IL混合物的表面形态、法向力和侧向力随电位的变化。
聚合阳离子在-1.0 V时强烈吸附于Au(111)并形成富含聚合阳离子的边界层。该边界层在开路电位（OCP）时与表面的结合较弱，在+1.0 V时结合更弱。由于与电极表面的电吸引作用，聚合阳离子链在-1.0 V和OCP时被压缩，但在+1.0 V时由于电排斥作用而完全伸展。5 wt% PIL/IL混合物在-1.0 V和OCP时的侧向力高于在+1.0 V时，因为富含聚合阳离子的边界层更粗糙且与原子力显微镜探针的相互作用更强；在+1.0 V时，侧向力较低，且由于边界层中聚合阳离子被常规阴离子取代，与纯常规离子液体相当。
