Mechanical and antibacterial behavior of multilayered geopolymer coatings on Ti6Al4V alloys

Geopolymers are commonly used in a wide range of applications including binders into the building industry, production of refractory elements, filtration systems, low CO2 emission applications, etc. Their production can be performed either by acidic or alkaline formulation. In the last 15 years, however, they have been proposed also in biomedical applications for bone tissue regeneration. The aim of this work is the preparation of a thin and homogeneous geopolymer coating on a Ti6Al4V alloy in order to test their futuristic application as coating of prosthetic devices made with this metal alloy. Multilayered coatings were therefore produced by mean of dip coating with the aim of verifying which formulation, acidic or alkaline maximize adhesion. The morphological and chemical characteristics of the coatings were analyzed and adhesion of geopolymers to the substrate was investigated by scratch tests. Finally, a bacterial growth test was performed to verify antibacterial properties of the coatings. Graphical abstract: [Figure not available: see fulltext.]