Ionic liquids on uncharged and charged surfaces: In situ microstructures and nanofriction

作     者：Rong AN Yudi WEI Xiuhua QIU Zhongyang DAI Muqiu WU Enrico GNECCO Faiz Ullah SHAH Wenling ZHANG Rong AN;Yudi WEI;Xiuhua QIU;Zhongyang DAI;Muqiu WU;Enrico GNECCO;Faiz Ullah SHAH;Wenling ZHANG

作者机构：Herbert Gleiter Institute of NanoscienceSchool of Materials Science and EngineeringNanjing University of Science and TechnologyNanjing 210094China High Performance Computing DepartmentNational Supercomputing Center in ShenzhenShenzhen 518055China Otto Schott Institute of Materials Research(OSIM)Friedrich Schiller University JenaJena 07743Germany Chemistry of InterfacesLuleåUniversity of TechnologyLulea 97187Sweden School of Mechanical EngineeringNanjing University of Science and TechnologyNanjing 210094China 

出 版 物：《Friction》 (摩擦（英文版）)

年 卷 期：2022年第10卷第11期

页      面：1893-1912页

核心收录：

学科分类：0817[工学-化学工程与技术] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0802[工学-机械工程] 0801[工学-力学（可授工学、理学学位）] 

基　　金：This work was supported by the Natural Science Foundation of Jiangsu Province(No.BK20191289) the National Natural Science Foundation of China(Nos.21838004,21978134,and 21676137) the National Key R&D Program of China(No.2018YFB0204403) the Swedish Research Council(No.2018-04133) the German Research Foundation,DFG(No.GN 92/16-1) 

主　　题：microstructure friction contact stiffness charged surfaces ionic liquids(ILs) molecular simulation 

摘      要：In situ changes in the nanofriction and microstructures of ionic liquids(ILs)on uncharged and charged surfaces have been investigated using colloid probe atomic force microscopy(AFM)and molecular dynamic(MD)*** representative ILs,[BMIM][BF_(4)](BB)and[BMIM][PF_(6)](BP),containing a common cation,were selected for this *** torsional resonance frequency was captured simultaneously when the nanoscale friction force was measured at a specified normal load;and it was regarded as a measure of the contact stiffness,reflecting in situ changes in the IL microstructures.A higher nanoscale friction force was observed on uncharged mica and highly oriented pyrolytic graphite(HOPG)surfaces when the normal load increased;additionally,a higher torsional resonance frequency was detected,revealing a higher contact stiffness and a more ordered IL *** nanofriction of ILs increased at charged HOPG surfaces as the bias voltage varied from 0 to 8 V or from 0 to−8 *** simultaneously recorded torsional resonance frequency in the ILs increased with the positive or negative bias voltage,implying a stiffer IL layer and possibly more ordered ILs under these *** simulation reveals that the[BMIM]+imidazolium ring lies parallel to the uncharged surfaces preferentially,resulting in a compact and ordered IL *** parallel“sleepingstructure is more pronounced with the surface charging of either sign,indicating more ordered ILs,thereby substantiating the AFM-detected stiffer IL layering on the charged *** in situ observations of the changes in nanofriction and microstructures near the uncharged and charged surfaces may facilitate the development of IL-based applications,such as lubrication and electrochemical energy storage devices,including supercapacitors and batteries.