title: Deposition Kinetics of Bioinspired Phenolic Coatings on Titanium Surfaces.
abstract: Polyphenols can form functional coatings on a variety of different materials through auto-oxidative surface polymerization in a manner similar to polydopamine coatings. However, the mechanisms behind the coating deposition are poorly understood. We report the coating deposition kinetics of the polyphenol tannic acid (TA) and the simple phenolic compound pyrogallol (PG) on titanium surfaces. The coating deposition was followed in real time over a period of 24 h using a quartz crystal microbalance with dissipation monitoring (QCM-D). TA coatings revealed a multiphasic layer formation: the deposition of an initial rigid layer was followed by the buildup of an increasingly dissipative layer, before mass adsorption stopped after approximately 5 h of coating time. The PG deposition was biphasic, starting with the adsorption of a nonrigid viscoelastic layer which was followed by layer stiffening upon further mass adsorption. Coating evaluation by ellipsometry and AFM confirmed the deposition kinetics determined by QCM-D and revealed maximum coating thicknesses of approximately 50 and 75 nm for TA and PG, respectively. Chemical characterization of the coatings and polymerized polyphenol particles indicated the involvement of both physical and chemical interactions in the auto-oxidation reactions.
authors.affiliation: Department of Biomaterials, Institute of Clinical Dentistry, University of Oslo , P.O. Box 1109 Blindern, 0317 Oslo, Norway.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Geißler
authors.affiliation: Department of Biomaterials, Institute of Clinical Dentistry, University of Oslo , P.O. Box 1109 Blindern, 0317 Oslo, Norway.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Barrantes
authors.affiliation: Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg , P.O. Box 412, 40530 Gothenburg, Sweden.
authors.forename: Pentti
authors.initials: P
authors.lastname: Tengvall
authors.affiliation: Department of Biomedical Engineering, Chemistry of Life Processes Institute, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Phillip B
authors.initials: PB
authors.lastname: Messersmith
authors.affiliation: Department of Biomaterials, Institute of Clinical Dentistry, University of Oslo , P.O. Box 1109 Blindern, 0317 Oslo, Norway.
authors.forename: Hanna
authors.initials: H
authors.lastname: Tiainen
mesh_terms: D059808:Polyphenols / Q000737:chemistry*; D011748:Pyrogallol / Q000737:chemistry*; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D059808:Polyphenols; D011748:Pyrogallol; D014025:Titanium