n naseh - Polymer Eng. and Color Tech. Department, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Iran.
m mohseni - Polymer Eng. and Color Tech. Department, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Iran.
b Ramezanzadeh - Polymer Eng. and Color Tech. Department, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Iran.

Producing automotive clearcoats with high self-cleaning capability needs two requirements: low surface energy (in this case the contaminations cannot wet the surface) [1-2] and high surfacecrosslink density to restrict contaminations penetrating into the surface [3]. Recent attempts are based on improving self-cleaningability of the clearcoats by changing both the surface chemistry and morphology. One way to reach this target without disturbing othercoating properties is using surface active additives. The chemical structure and molecular weight of an additive are importantparameters affecting its properties. In this study, two siliconmodified additives with different functionalities and molecular weights are used to modify the surface chemistry and mechanicalproperties of an acrylic/melamine clearcoat