Step 1:Functionalization 196 Surface charge of graphite flakes 1.Superparamagnetic 0 iron oxide nanoparticles: 1 (A)lenuanod eaz FeaO4 2- 2.Coat Fe3O4 with a cationic dispersant 31 3.Fe3O and graphite interact through 78 electrostatic force 9 1011 a Graphite functionalization FegOa 101m 500nm Graphite flakes 1111 Step 1: Functionalization Surface charge of graphite flakes 1. Superparamagnetic iron oxide nanoparticles: Fe3O4 2. Coat Fe3O4 with a cationic dispersant 3. Fe3O4 and graphite interact through electrostatic force