Substrate effects on the surface properties of nylon 6

Abstract Thin nylon 6 films spin coated onto different substrates were characterized by wide-angle X-ray scattering (WAXS), Fourier transformation infrared (FTIR) spectroscopy, FTIR trichroic analysis and water contact angle (CA) measurements. The morphology and hydrophilicity of the nylon 6 surface were found to be greatly influenced by the nature of the substrate. The film surface contained primarily α-form crystals when it was prepared using hydrophobic substrates. This film was more hydrophobic. However, for hydrophilic substrates, the film surface comprised mainly γ-form crystals and demonstrated greater hydrophilicity. FTIR trichroic analysis of the N H stretching vibration mode revealed that the presence of a hydrophilic substrate caused the N H stretching bonds on the film surface to align preferentially in the direction perpendicular to the surface. Such effects were attributed to molecular interactions between the N H bonds of the polymer and Si O bonds of the hydrophilic substrate.