Impact of Perfluoro and Alkylphosphonic Self-Assembled Monolayers on Tribological and Antimicrobial Properties of Ti-DLC Coatings.

Michal Cichomski,Natalia Wrońska,Anna Jędrzejczak,Milena Prowizor,Ireneusz Piwoński,Katarzyna Lisowska,Mariusz Dudek,Ewelina Borkowska,Damian Batory

doi:10.3390/ma12152365

Michal Cichomski, Natalia Wrońska + Show 7 more

Open Access

https://doi.org/10.3390/ma12152365

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Journal: Materials	Publication Date: Jul 25, 2019
Citations: 9	License type: CC BY 4.0

Affiliation: University of Łódź, Lodz University of Technology

Abstract

The diamond-like carbon (DLC) coatings containing 1.6%, 5.3% and 9.4 at.% of Ti deposited by the radio frequency plasma enhanced chemical vapor deposition (RF PECVD) method on the silicon substrate were modified by n-decylphosphonic acid (DP) and 1H, 1H, 2H and 2H-perfluorodecylphosphonic acid (PFDP). The presence of perfluoro and alkylphosphonic self-assembled monolayers prepared by the liquid phase deposition (LPD) technique was confirmed by Fourier transform infrared spectroscopy (FTIR). It was shown that DP and PFDP monolayers on the surface of titanium incorporated diamond-like carbon (Ti-DLC) coatings had a huge influence on their wettability, friction properties, stability under phosphate- and tris-buffered saline solutions and on antimicrobial activity. It was also found that the dispersive component of surface free energy (SFE) had a significant influence on the value of the friction coefficient and the percentage value of the growth inhibition of bacteria. The dispersive component of SFE caused a reduction in the growth of bacteria and the friction coefficient in mili- and nano-newton load range. Additionally, both self-assembled monolayers prepared on Ti-DLC coatings strongly reduced bacterial activity by up to 95% compared to the control sample.

Highlights

Carbon-based coatings have enjoyed growing interest and can be successfully used in the electronics and microelectronics, especially in micro/nanoelectromechanical systems (MEMS/NEMS) [1,2]
In order to understand these phenomena, we presented the influence of the acid-base and dispersive components of surface free energy (SFE) on the friction coefficient and on the antibacterial activity, which no research was reported before
The chemical structure of investigated compounds had a huge influence on wettability, The presence of self-assembled layers on the surface of the Ti-diamond-like carbon (DLC) was confirmed by using Fourier friction properties, stability under phosphate- and tris-buffered saline solutions and antimicrobial transform infrared spectroscopy

Summary

Introduction

Carbon-based coatings have enjoyed growing interest and can be successfully used in the electronics and microelectronics, especially in micro/nanoelectromechanical systems (MEMS/NEMS) [1,2]. The possibility of using DLC is wide but the high internal stresses occurring in the coating is a major problem that may result in poor adhesion to the substrate and a tendency to delamination. The use of dopants in DLC structure is the most effective method for solving this problem [7,8,9]. It is important to find a dopant that allows reducing the internal stresses while. The radio frequency plasma enhanced chemical vapor deposition (RF PECVD) method is one the most important techniques that allow for deposition of good quality pure and doped DLC coatings. The method is easy to implement in the industry and allows the use of different precursors containing dopant atoms (e.g., titanium) to improve mechanical properties [2,11,12]

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