Surface Modification of Ti45Nb Alloy with an Alkylphosphonic Acid Self-Assembled Monolayer

Abstract

A new low-modulus β Ti−Nb alloy with low elastic modulus and excellent corrosion resistance is currently under consideration as a surgical implant material. The usefulness of such materials can be dramatically enhanced if their surface structure and surface chemistry can be controlled. This control is achieved in two stages. Electropolishing and anodic oxidation of the Ti45Nb alloy provide a surface with a uniform oxide layer that is a mixture of TiO2 and Nb2O5. The impact of each of these two steps on the morphology of the surface and on the thickness and chemistry of the oxide layer has been assessed. In addition, as a first step toward controlling the surface chemistry of this material, a self-assembled monolayer (SAM) based on hexadecylphosphonic acid (HDPA) is attached to the anodized surface. The SAM is characterized based on its wetting properties and by Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis. Using variable angle XPS analysis, detailed information is obtained about the orientation and structure of the SAM, its thickness, and the chemistry of its interaction with the metal oxide surface of the alloy. Further support for the creation of a true monolayer film is obtained from FTIR measurements on a model oxide surface analogous to that of the alloy. This is the first report of SAM attachment to this alloy and opens the possibility of monolayer control of its biocompatibility.

Analysis of the surface density and reactivity of perfluorophenylazide and the impact on ligand immobilization

“…In addition, the methylene stretching frequencies are characteristics for the degree of ordering in organic layers. [24][25][26][27] Measured methylene asymmetric stretching frequencies of 2920 cm À1 for the PFPA-MUTEG/MDEG mixed films prepared from 90:10 and 80:20 solutions versus a value of 2924 cm À1 for the 100% PFPA-MUTEG suggest that the mixed film have a slightly higher degree of order.…”

Organic corrosion inhibitors: where are we now? A review. Part IV. Passivation and the role of mono- and diphosphonates

“…The high corrosion resistance of this light metal and its alloys in many corrosive environments at normal temperatures is well known, so it is not surprising that they are used as medical implants [69][70][71][72][73][74][75][76]. The utility of these materials can be greatly increased if the structure and chemistry of their surfaces can be controlled.…”

“…The utility of these materials can be greatly increased if the structure and chemistry of their surfaces can be controlled. For this purpose, an alloy, for example Ti45Nb, is first polished and anodized, providing a surface with a uniform oxide layer (a mixture of TiO 2 and Nb 2 O 5 ) [70]. After that a SAM formed by APhC 16 is attached to the anodized surface.…”

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“…Titanium and its alloy are widely studied with many advantages, such as corrosion resistance, higher strength to weight ratio, biocompatibility, and good temperature resistance [1][2][3]. Currently, it has been extensively applied in aerospace, medicine, navigation, and catalytic industries.…”