Physico-Chemical Surface Modifications of Polyetheretherketone (PEEK) Using Extreme Ultraviolet (EUV) Radiation and EUV-Induced Nitrogen Plasma

Abstract

In this work, the effect of extreme ultraviolet (EUV) radiation and the combination of EUV radiation and low-temperature nitrogen plasma on the physico-chemical properties of polyetheretherketone (PEEK) surfaces were presented. The laser-plasma EUV source based on a double gas puff target was used in this experiment to irradiate PEEK surfaces with nanosecond pulses of EUV radiation and to produce low-temperature plasma through the photoionization of nitrogen with EUV photons. The changes in surface morphology on irradiated polymer samples were examined using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Chemical changes of the PEEK surfaces were analysed using X-ray photoelectron spectroscopy (XPS). EUV radiation and nitrogen plasma treatment caused significant changes in the topography of modified PEEK’s surfaces and an increase in their average roughness. Strong chemical decomposition, appearance of new functional groups as well as incorporation of nitrogen atoms up to ~17 at.% on the PEEK’s surface were observed.

Characteristics of Hybrid Bioglass-Chitosan Coatings on the Plasma Activated PEEK Polymer

“…To overcome this problem, various chemical and physical modifications of the top polymer layer are used. For example: sandblasting [ 6 ], plasma treatment [ 7 ], acid etching [ 8 ], laser processing [ 9 ], and the deposition of bioactive substances, such as polysaccharides, sterols, peptides, phospholipids, hydroxyapatite, or titanium layers [ 4 , 10 , 11 , 12 ]. One of the biocompatible, degradable, and non-toxic polysaccharides is chitosan (Chit).…”

Efficient Osteogenic Activity of PEEK Surfaces Achieved by Femtosecond Laser–Hydroxylation

“…Moreover, the amount of C–OH on the surface is increased after hydroxylation compared to FPEEK, replacing the CO bond with more C–OH (Figure l,m). It is noteworthy that the −OH (water) peaks detected at 535.4 and 535.8 eV are likely attributed to water adsorbed on the sample surface after being exposed to air …”

“…It is noteworthy that the −OH (water) peaks detected at 535.4 and 535.8 eV are likely attributed to water adsorbed on the sample surface after being exposed to air. 36 Taken together, FSL treatment yields amorphous carbon and C−OH on the PEEK surface, which can facilitate bone-like apatite formation, as well as cell proliferation and osteogenic differentiation. 37 Importantly, the FSL treatment yields amorphous carbon and activates the C�O covalent bonds (FSL dissociates the PEEK molecular chain, reducing the C�O bond energy to an unstable state that is susceptible to a reaction with other groups, i.e., activation) on the surface, allowing for successful grafting of more C−OH groups with NaOH, 37,38 which would affect the hydrophilicity and bioactivity of the PEEK material.…”

“…Moreover, the amount of C−OH on the surface is increased after hydroxylation compared to FPEEK, replacing the C�O bond with more C−OH (Figure3l,m). It is noteworthy that the −OH (water) peaks detected at 535.4 and 535.8 eV are likely attributed to water adsorbed on the sample surface after being exposed to air 36. Taken together, FSL treatment yields amorphous carbon and C−OH on the PEEK surface, which can facilitate bone-like apatite formation, as well as cell proliferation and osteogenic differentiation 37.…”

Ion Bombardment-Induced Nanoarchitectonics on Polyetheretherketone Surfaces for Enhanced Nanoporous Bioactive Implants

“…This process is also observed in the O 1s spectra where we observe after deconvolution the presence of −OH from −CO 2 H and adsorbed water on the surface. 45,46 Detailed information on the modified PEEK surface from the fitted XPS spectra of C 1s and O 1s was obtained, and the following deductions could be made. Except for the π−π* shakeup peak, all other functionalities were assigned as Gaussian peaks.…”