Comparison of the Physicochemical Properties of Carboxylic and Phosphonic Acid Self-Assembled Monolayers Created on a Ti-6Al-4V Substrate

Michal Cichomski; Milena Prowizor; Dorota Anna Kowalczyk; Andrzej Sikora; Damian Batory; Mariusz Dudek

doi:10.3390/ma13225137

Comparison of the Physicochemical Properties of Carboxylic and Phosphonic Acid Self-Assembled Monolayers Created on a Ti-6Al-4V Substrate

Materials (Basel). 2020 Nov 14;13(22):5137. doi: 10.3390/ma13225137.

Authors

Michal Cichomski¹, Milena Prowizor¹, Dorota Anna Kowalczyk², Andrzej Sikora³, Damian Batory⁴, Mariusz Dudek⁵

Affiliations

¹ Department of Materials Technology and Chemistry, University of Lodz, Faculty of Chemistry, Pomorska 163, 90-236 Lodz, Poland.
² Department of Solid State Physics, Faculty of Physics and Applied Informatics, University of Lodz, Pomorska 149/153, 90-236 Lodz, Poland.
³ Department of Nanometrology, Faculty of Microsystem Electronics and Photonics, Wroclaw University of Science and Technology, Janiszewskiego 11/17, 50-372 Wrocław, Poland.
⁴ Department of Vehicles and Fundamentals in Machine Design, Lodz University of Technology, Stefanowskiego 1/15, 90-924 Lodz, Poland.
⁵ Institute of Materials Science and Engineering, Lodz University of Technology, Stefanowskiego 1/15, 90-924 Lodz, Poland.

Abstract

This study compared the tribological properties in nano- and millinewton load ranges of Ti‑6Al-4V surfaces that were modified using self-assembled monolayers (SAMs) of carboxylic and phosphonic acids. The effectiveness of the creation of SAMs with the use of the liquid phase deposition (LPD) technique was monitored by the contact angle measurement, the surface free energy (SFE) calculation, X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR) measurements. The obtained results indicated that more stable and well-ordered layers, which were characterized by the lowest values of the coefficient of friction, adhesion, and wear rate, were obtained using phosphonic acid as a surface modifier. Based on the obtained results, it was found that the Ti-6Al-4V alloy modified by phosphonic acid would be the most advantageous for practical applications, especially in micro- and nanoelectromechanical systems (MEMS/NEMS).

Keywords: Ti-6Al-4V alloy; adhesion; carboxylic/phosphonic acid; friction; nano-/microtribology.