Construction of octadecyltrichlorosilane self-assembled monolayer on stainless steel 316L surface

Alkyltrichlorosilane self-assembled monolayer (SAM) was regarded as the most stable SAM on silicon/silica substrate, but it was rarely coated on stainless steel 316L (SS316L) substrate surface due to the serious surface corrosion caused by the hydrochloric acid released during the hydrolysis process of alkyltrichlorosilane molecules. In this paper, a novel technical route aiming at constructing solid octadecyltrichlorosilane (OTS) SAM on SS316L surface was put forward. By prolonging the storage time of OTS–toluene reaction solution and adding a moderate amount of alkali into the reaction solution, a well-ordered and integrated OTS SAM was successfully coated on SS316L surface. The obtained OTS SAM was characterized by contact angle, atomic force microscopy (AFM), scanning electron microscope (SEM) and attenuated total reflectance Fourier transform infrared (ATR-FTIR). The long-term in vitro stability study of OTS SAM on SS316L showed that, even immersed in physiological saline or phosphate buffered saline (PBS) solution at 37 °C for up to 60 days, the sample surface still kept a typical hydrophobicity.