PDMS Surface Modification chemical 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. 

Diverse approaches have been considered in an attempt to enhance the cell attachment to the surface of PDMS implants [60]. In general, techniques that involve modification of the material surface are preferred to preserve the bulk properties. Chemical and physical surface modification methods, such as bonding of molecules, grafting of polymers and coating with bioactive materials, have shown different degrees of success over recent years. 

The chemical modification techniques refer to the treatments used to modify the chemical compositions of polymer surfaces. Those can also be divided into two categories modification by direct chemical reaction with a given solution (wet treatment) and modification by covalent bonding of suitable macromolecular chains to the polymer surface (grafting). Among these techniques, surface grafting has been widely used to modify the surface of PDMS. 

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