Local chemical modification surface grafting

A comparison of HMDS with PDMS indicates the impact of surface modification on the local hardness of the silica particles. Pure HMDS modification only increases the hydrophobicity by formation of a hard monolayer of trimethylsiloxy groups. Thus, HMDS-treated silicas seemed to give weaker interaction with the toner resin surfaces, and a smaller amount of particles can be found on the toner surface. The PDMS modification leads to a softer, polymer-like grafting. This grafted layer can interact with the toner resin surface, leading to stronger adhesion of the particles. PDMS/HMDS-treated silicas are covered by a PDMS layer which is not chemically bonded. Thus, silica particles can be removed while PDMS stay on the toner surface. 

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