Sol-gel coatings made using methyl-modified alkoxysilanes: The balance between protection and bioactivation

authors	Romero-Gavilan, F; Carlos-Almeida, J; Cerqueira, A; Gurruchaga, M; Goni, I; Miranda-Salvado, IM; Fernandes, MHV; Suay, J
nationality	International
journal	PROGRESS IN ORGANIC COATINGS
author keywords	Hybrid sol-gel; Biomaterials; Alkoxysilane; Metal prosthesis; Corrosion resistance; Coating
keywords	HYBRID MATERIALS; FT-IR; IMPLANTS; TITANIUM; HYDROLYSIS; WETTABILITY; DEGRADATION; SILOXANE
abstract	The reported osteogenic properties of the hybrid silica sol-gel materials make these compositions perfect candidates for bone tissue engineering applications. The aim of this study was the synthesis and characterisation of hybrid silica coatings, obtained using mixtures of tetraethyl orthosilicate (TEOS) and three different methyl-modified alkoxysilanes: trimethoxymethylsilane (MTMS), dimethyldiethoxysilane (DMDES) or polydimethylsiloxane (PDMS). A comparison of the properties of these materials can reveal the best candidate for the coatings on metallic prostheses. After optimising the synthesis parameters, the developed coatings were characterised using Fourier transform infrared spectrometry (FT-IR), H-1 and Si-29 solid-state nuclear magnetic resonance (H-1-NMR and Si-29-MNR), cross-cut tests, scanning electron microscopy (SEM), contact angle measurements, optical profilometry, hydrolytic degradation tests and electrochemical corrosion analysis. Homogeneous and well-adhering coatings were obtained using the three methyl-modified reagents. However, different degrees of protection against corrosion, different hydrophilicity and varying degradation kinetics were observed for different precursors. The MTMS-based coating showed the highest hydrophilicity and degradation kinetics; these properties can be associated with increased bioactivity (Si release). In contrast, the PDMS and DMDES-based coatings showed augmented resistance to corrosion and lower permeability to water and, consequently, improved protection of metallic surfaces. From the physicochemical point of view, all these materials displayed interesting characteristics, relevant for coatings to be used in biomedical applications.
publisher	ELSEVIER SCIENCE SA
issn	0300-9440
isbn	1873-331X
year published	2020
volume	147
digital object identifier (doi)	10.1016/j.porgcoat.2020.105770
web of science category	Chemistry, Applied; Materials Science, Coatings & Films
subject category	Chemistry; Materials Science
unique article identifier	WOS:000568708300005