A Novel Approach for the Decoration of Parylene C Coatings Using Functional Silica-Triclosan Co-Polymer Nanoparticles

Both pure silica (SiO2) nanoparticles (SNPs) and functionalized hybrid triclosan (TCS)/silica nanocomposites (T-SNCs) were deposited onto nonfunctional Parylene C films using a novel, readily executed, one-step decoration method. Unlike previously known methods, this functionalization method of Parylene C films required neither any binding agent nor sophisticated equipment/devices. The SiO2-based NPs anchored onto Parylene C substrates were formed via a common base-catalyzed hydrolytic sol-gel method. Regarding the mechanism, it has been assumed that the SiO2 phase precursor (Si(OC2H5)4), tetraethoxysilane (TEOS), was first adsorbed and 2D polymerized onto the parylene C film due to hydrophobic interactions that served as an anchor mechanism for further corresponding NPs growth [1] This assumption was investigated by comparing thermal behaviors (measured by differential scanning calorimetry, DSC) of parylene C coatings before and after the following specific surface treatment, i.e., first (i) first parylene C coating incubation with TEOS, followed by (ii) SNPs formation and growth from such a TEOS-modified coating surface. Following the same procedure, hybrid thiophene-containing H-SiO2-TCS NPs were also successfully grown from the surface of a same TEOS-modified parylene C film and characterized using high resolution scanning electron microscopy (HR-SEM) and X-ray photoelectron spectroscopy (XPS). In order to obtain deeper insight into the overall functionalization process, the similar hybrid H-SiO2-TCS NPs that formed in the bulk-contacting medium were also isolated and fully characterized for comparison needs. Resulting anti-bacterial biological experiments were also performed as well.