Surface Reduction of Poly(aryl ether ether ketone) Film:  UV Spectrophotometric, ³H Radiochemical, and X-ray Photoelectron Spectroscopic Assays of the Hydroxyl Functions

Abstract

The surface reduction of amorphous poly(aryl ether ether ketone) (PEEK) film was successfully achieved by wet chemistry using a solution of NaBH4 in DMSO at 120 °C for 3 h. The resulting PEEK-OH film was fully characterized by MIR, UV−visible, and 1H NMR spectroscopies; all the data were consistent with those of the references, 4-(4-methoxyphenoxy)benzhydrol and bulk-reduced PEEK (“PEEK-OH”). The surface of PEEK-OH film was analyzed by X-ray photoelectron spectroscopy (XPS). From the fine structures of the C1s and O1s peaks, we could determine a ratio of reduction reaching 75−85% of the monomer units contained in the 10 outermost atomic layers. The surface reactivity of the hydroxyl groups was assayed by derivatization with [3H]acetic anhydride followed by liquid scintillation counting (LSC) of the sample-associated radioactivity. The PEEK-OH film was reacted with p-nitrophenyl chloroformate to furnish an activated surface (PEEK-OCO2PNP), the basic hydrolysis of which allowed the indirect spectrophotometric assay of the reactive OH groups. The PEEK-OCO2PNP film was further used to covalently fix amine derivatives via a carbamate linkage. Using [3H]lysine and trifluoroethylamine, we were able to assay the surface reactivity by LSC and XPS respectively. The ratios of surface derivatization were within 5−30%. The PEEK-OH film was used as substrate for the cultivation of CaCo2 epithelial cells; the presence of surface hydroxyl functions moderately improves the polymer biocompatibility.

Covalent attachment of cell-adhesive peptide Gly-Arg-Gly-Asp (GRGD) to poly(etheretherketone) surface by tailored silanization layers technique

“…On the other hand, highresolution O1s spectra (Fig. 3c) [7]. Additionally, the surface oxygen content and the chemical component ratio (O1s/C1s) were increased after hydroxylation reaction (Table 2), which was consistent with the study of Noiset et al [7].…”

“…3c) [7]. Additionally, the surface oxygen content and the chemical component ratio (O1s/C1s) were increased after hydroxylation reaction (Table 2), which was consistent with the study of Noiset et al [7]. Furthermore, after hydroxylation of PEEK, the existence of surface hydroxyl groups improved the surface wettability, and then the contact angle of the surface decreased from 90.2 • to 82.6 • (Fig.…”

“…All the above-mentioned reasons have largely made PEEK an attractive implant material for biomedical applications. However, the native PEEK surface is bioinert and does not support cellular adhesion [7].…”

“…Organosilanes have been introduced onto PMMA surface after hydroxylation pretreatment via water-vapor plasma treatment or lithium aluminum hydride reduction [17,18]. Fortunately, although it is difficult to functionalize PEEK because of its insolubility in most of organic solvents, the carbonyl groups in the benzophenone can be effectively reduced to hydroxyl groups and the process has been extensively studied by Noiset et al [7]. To our knowledge, few studies have been conducted on the use of silanization technique to attach RGD on PEEK surface.…”

Surface functionalization of PEEK films studied by time-of-flight secondary ion mass spectrometry and x-ray photoelectron spectroscopy

“…In the PEEK-OH Ðlms, the carbonyl band due to the PEEK benzophenone motif (1655 cm~1) was signiÐcantly diminished. 30 The PEEK-COOH samples displayed new bands at 1740 cm~1 and 1649 cm~1, attributed respectively to the carboxyl and amide functions. 31 In the sample, PEEK-NHCO 2 Ph the carbamate function was visible at 1739 cm~1 ; this new band disappeared totally when the polymer was transformed into Finally, PEEK-PEEK-NH 2 .32 FMOC was characterized by the appearance of a broad band at 1742 cm~1 (carboxyl and carbamate functions), which signiÐcantly diminished after deprotection into PEEK-glutamine.…”