Formation and properties of surface-anchored amine-terminated poly(dimethylsiloxane) assemblies with tunable physico-chemical characteristics

Surface-anchored amine-terminated poly(dimethysiloxane) (PDMS) assemblies with tunable physico-chemical characteristics were fabricated with a simple two-step procedure. Firstly, 3-glycidoxypropylmethyldimethoxysilane (GPDMS) molecules were self-assembled on silicon surface, and then coupled to PDMS through a surface ring-opening reaction. The structure and morphology of the amine-terminated PDMS assemblies were characterized with various techniques such as ellipsometry, contact angle goniometer, grazing angle attenuated total reflectance-Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. The GPDMS monolayers were truly monomolecular films with a virtually normal molecular orientation of densely packed molecules, which were firmly tethered to the hydroxylated silicon substrate. Self-assembly of PDMS molecules resulted in the formation of homogeneous films ~ 6.3 nm thick with the surface roughness ~ 0.898 nm. The calculation of grafting parameters from experimental measurements indicated that the presence of homogeneous and densely grafted PDMS films allowed us to predict a “brushlike” regime for the polymer chains in good solvents.