1. Center for Microengineered Materials, Department of Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131, Tokai Carbon Co., Ltd., Fuji Research Laboratory, 394-1 Subashiri Oyama-Cho, Sunto-Gun, Shizuoka-ken, 410-1431, Japan, and Institut de Chimie des Surfaces et Interfaces, CNRS, 15, rue Jean Starcky, B.P. 2488, F-68057 Mulhouse Cedex, France