Interaction Forces Between Graphitic Carbon Black Surfaces Coated with Polymers Using Atomic Force Microscopy

Abstract

Carbon black dispersions are stabilized using polymeric dispersants. The stabilization is provided by adsorbed polymer layers around surfaces through interaction forces. Therefore, it is valuable to measure the interaction forces between bare and polymer-coated surfaces using atomic force microscopy to predict the behavior of dispersions. Three polymeric dispersants (Hypermer LP1, Hypermer B246, and OLOA 11000) are used in the present work to disperse the graphitic carbon black particles in an organic solvent, decaline. Hypermer B246 and OLOA 11000 produced repulsive interactions and, hence, are effective stabilizers for carbon black surfaces. Hypermer LP1 produced attractive interactions, making it an ineffective stabilizer for carbon black. Attractive interactions were also observed in blank dispersions. The experimentally determined interaction curves are compared with theoretical curves, the Derjaguin approximation. The repulsive steric interactions are also analyzed quantitatively based on the Alexander and de Gennes scaling law.

Keywords:

• AFM (atomic force microscopy)
• colloidal interactions
• dispersions
• polymeric dispersants

ACKNOWLEDGMENTS

The authors would like to acknowledge the generous help provided by Eiman Al-Muhareb in setting up AFM.

Notes

Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/ldis.