电解质吸附对水基带电表面黏着的影响  

Effect of Electrolyte Adsorption on Adhesion between Charged Surfaces in Aqueous Conditions

作　　者：吴波[1] 张传伟[1] 渠达[1] 李臻[1] 王廷剑 古乐[1] WU Bo;ZHANG Chuanwei;QU Da;LI Zhen;WANG Tingjian;GU Le(School of Mechatronics Engineering,Harbin Institute of Technology,Heilongjiang Harbin 150001,China)

机构地区：[1]哈尔滨工业大学机电工程学院,黑龙江哈尔滨150001

出　　处：《摩擦学学报》2022年第6期1207-1215,共9页Tribology

基　　金：国家重点研发计划(2018YFB2000300);国家自然科学基金(U1737204);中国博士后科学基金(2021M693724)资助。

摘　　要：为研究界面黏着,利用表面力仪在高离子强度电解质水溶液中测量负电云母表面之间的法向力.在纯水中,因范德华吸引,两表面跳跃至直接接触(间距0A),分离两表面时测得界面黏着力为-46.7 m N/m.在0.1 mol/L K_(2)SO_(4)中,因K^(+)离子牢固吸附于云母,表面间距稳定于5A,黏着力仅-2.9 m N/m;在0.1 mol/L Ca(NO_(3))_(2)中,云母表面吸附的Ca^(2+)离子产生显著短程水合排斥,但在较低载荷下解吸附,导致两表面直接接触,黏着力高达-40.7 m N/m.加入Ca(OH)_(2)于0.1 mol/L K_(2)SO_(4)仅产生微弱短程排斥,黏着状态几乎与纯K_(2)SO_(4)水溶液中相同.聚电解质PCE从0.1 mol/L K_(2)SO_(4)中吸附于云母表面且诱导远程空间位阻排斥,但在中等载荷下解吸附,导致两表面轻度黏着(间距5A);牢固吸附于云母表面的PNS高分子薄膜之间的空间位阻完全阻止云母界面黏着.牢固吸附是电解质吸附层稳定阻止界面黏着的必要条件.In order to investigate interfacial adhesion behaviors,normal interaction forces between negatively charged mica surfaces were directly measured in various electrolyte aqueous solutions at high ionic strength with the wellestablished surface forces apparatus technique,which had distance and force measuring resolutions of down to 1A and ~10 n N,respectively.In pure water,a weak but long-range electrostatic repulsion force between the surfaces was detected and this interaction force gradually increased as the surfaces were slowly approached.When approaching the surfaces to a separation of less than 50A,the lower mica surface supported by a cantilever spring suddenly jumped to the fixed upper mica surface because of the van der Waals attraction between the mica substrates,resulting in direct contact of the two mica surfaces at separation of 0A.Upon subsequently separating the two surfaces,an interfacial adhesive force of about -46.7 m N/m was measured when the lower mica surface jumped out of contact from the upper mica surface.In comparison,the electrostatic repulsion effect between the mica surfaces was totally screened in 0.1mol/L K_(2)SO_(4)solution due to high ionic strength and no interaction force was detected before the surfaces came into the similar jump-into contact.Since K^(+)ions electrostatically adsorbed onto the negatively charged mica surfaces robustly,the separation between the surfaces maintained at around 5A even though the surfaces came into hard wall contact,and the adhesive force measured at the jump-out moment was remarkably lowered to about -2.9 m N/m.In 0.1 mol/L Ca(NO_(3))_(2)solution,Ca^(2+)ions also bound onto mica because of electrostatic attraction,but the adsorption of Ca^(2+)ions induced a significant short-range hydration repulsion between the two surfaces,rather than electrostatic repulsion.Such hydration interaction force was not detected in the monovalent K_(2)SO_(4)solution.The binding strength of Ca^(2+)ion hydration layers on mica was weak so that the adsorbed Ca^(2+)ions compl

关 键 词：黏着 吸附 水合作用 空间位阻 电解质 表面力 

分 类 号：TH117[机械工程—机械设计及理论]