In-vitro bioactivity investigation and surface properties of a PMMA-SiO 2 composite coating on SS-316L using the Sol-Gel technique

Abstract

Surface modification of SS-316L using an organic and inorganic hybrid coating of polymethyl methacrylate (PMMA) and silicon dioxide (SiO₂) is being conducted in the current investigation with crosslinking agent 3-aminopropyl tri-ethoxy silane (APTES). The solvent-gel method and dip coating with varying amount of SiO₂ (i.e. 0.5, 1, and 1.5 wt.%) is used for surface modification. On the coated surface, Fourier transform infrared spectroscopy (FTIR) at 1000–1250 cm⁻¹ reveals the crosslinking of silicon and PMMA. The coatings formed on SS-316L are homogenous, transparent, and free of defects and voids when seen macroscopically. A good crystallinity and presence of coated material can be seen from the X-ray diffraction and microstructure analysis of coated surface. The PMMA coating with 1.5 wt.% SiO₂ has the most apatite crystals deposited on surface as observed with 7 days of immersion on simulated body fluid (SBF). These findings provide a solid link that coating SS-316L with SiO₂ promotes bone bioactivity, and the PMMA+1.5 wt.% SiO₂ coating can be employed on implants. The results of this study suggest a sustainable coating solution for improved bioactivity in medical applications and surgical instruments.