1. Key laboratory of Colloid and Interface Chemistry, Shandong University; Ministry of Education; Jinan 250100, P. R. China
2. College of Chemistry, Chemical Engineering and Materials Science; Shandong Normal University; Jinan 250014, P. R. China
3. Petroleum Engineering Technology Research Institute of Shengli Oilfield, Sinopec; Dongying 257000, P. R. China