1. Key Laboratory for Colloid and Interface Chemistry (Shandong University), Ministry of Education, Jinan 250100, P. R. China, State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China, and Physikalische Chemie I, Universität Bayreuth, D-95440 Bayreuth, Germany