title: Experimental observation of the ion-ion correlation effects on charge inversion and strong adhesion between mica surfaces in aqueous electrolyte solutions.
abstract: Direct force measurements between two mica surfaces in aqueous electrolyte solutions over broad ranges of LaCl3 concentrations and pH values were carried out with a surface forces apparatus. Charge inversion on mica surfaces is detected once the LaCl3 concentration reaches a critical value. With the continual increase of LaCl3 concentrations, the mica surface will be overscreened by the counterions. It is demonstrated that the two mica surfaces may experience the jump-in contact even at high LaCl3 concentrations, which is seldom seen in monovalent salt solutions. The strong adhesion cannot be attributed to the van der Waals force alone, but should include the ion-ion correlation forces. Through adjusting the pH values in LaCl3 solutions, the ion-ion correlation force can be evaluated quantitatively. These results provide important insight into the fundamental understanding in the role of ion-ion correlations in ion screening mechanism and interactions between charged objects.
authors.affiliation: School of Mechanical Engineering and Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, Southeast University , Nanjing 211189, People's Republic of China.
authors.forename: Qiyan
authors.initials: Q
authors.lastname: Tan
authors.forename: Gutian
authors.initials: G
authors.lastname: Zhao
authors.forename: Yinghua
authors.initials: Y
authors.lastname: Qiu
authors.forename: Yajing
authors.initials: Y
authors.lastname: Kan
authors.forename: Zhonghua
authors.initials: Z
authors.lastname: Ni
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D004573:Electrolytes / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000737:chemistry; D007811:Lanthanum / Q000737:chemistry*; D012996:Solutions; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D000538:Aluminum Silicates; D004573:Electrolytes; D007477:Ions; D012996:Solutions; C028521:lanthanum chloride; D014867:Water; D007811:Lanthanum; C011934:mica