1. Department of Chemical Engineering, National Taiwan University, 1 Roosevelt Road, Sec. 4, Taipei, 106 Taiwan, Chemical Engineering Department, National Taiwan University of Science and Technology, 43, Keelung Road, Sec. 4, Taipei, 106 Taiwan, and Max-Planck-Institut für Kolloid- und Grenzflächenforschung, Max-Planck-Campus, Haus 2, Am Mühlenberg 2, D-14476 Golm/Potsdam, Germany