Application Of Phenol/Amine Copolymerized Film Modified Magnesium Alloys: Anticorrosion And Surface Biofunctionalization

Abstract

Magnesium metal as degradable metallic material is one of the most researched areas, but its rapid degradation rate restricts its development. The current anticorrosion surface modification methods require expensive equipment and complicated operation processes and cannot continue to introduce biofunction on modified surface. In this study, the GAHD conversion coatings were fabricated on the surface of magnesium alloys (MZM) by incubating in the mixture solution of gallic acid (GA) and hexamethylenediamine (HD) to decrease the corrosion rate and provide primary amines (-NH2), carboxyl (-COOH), and quinone groups, which is supposed to introduce biomolecules on MZM. Chemical structures of the MZM-GAHD and MZM-HEP-GAHD were explored by analyzing the results of FTIR and XPS comprehensively. Furthermore, it was proved that the heparin (HEP) molecules were successfully immobilized on MZM-GAHD surface through carbodiimide method. The evaluation of platelet adhesion and clotting time test showed that MZM-HEP-GAHD had higher anticoagulation than MZM-GAHD. Through electrochemical detection (polarization curves and electrochemical impedance spectroscopy Nyquist spectrum) and immersion test (Mg(2+) concentration and weight loss), it was proved that compared to MZM, both the MZM-GAHD and MZM-HEP-GAHD significantly improved the corrosion resistance. Finally, in vivo experimentation indicated that mass loss had no significant difference between MZM-1:1, MZM-HEP-1:1, and MZM. However, the trend still suggested that MZM-1:1 and MZM-HEP-1:1 possessed corrosion resistance property.

Sealing the Pores of PEO Coating with Mg-Al Layered Double Hydroxide: Enhanced Corrosion Resistance, Cytocompatibility and Drug Delivery Ability

“…According to the corrosion reaction of Mg + H 2 O → Mg 2+ + OH − + H 2 (gas), both the hydrogen evolution and the change of pH value can reflect the corrosion rate of the sample 32 , 33 . Figure 6b and c exhibit the hydrogen evolution and the corrosion rate of all samples.…”

Phenolic Modified Ceramic Coating on Biodegradable Mg Alloy: The Improved Corrosion Resistance and Osteoblast-Like Cell Activity

“…According to the published data of XPS spectra for C 1s of MAO and MAO-GA, 284.7 eV and 285.9 eV were attributed to aliphatic C and C–O, respectively ( Figure 4 a) [ 26 ]. In addition, 288.6 eV was ascribed to COOH, COOR, COO − and C=O (quinonyl) [ 27 ]. The area ratio of the carboxyl related group for the MAO-GA group, which is the characteristic of GA, was around 22%, proving that GA immobilizes on the MAO coating after the sample is immersed for 24 h. For O 1s, 530.9 eV belongs to aromatic C=O and magnesium oxide, while 531.7 eV is ascribed to O=C–OH and magnesium hydroxide ( Figure 4 b).…”

“…The area ratio of the carboxyl related group for the MAO-GA group, which is the characteristic of GA, was around 22%, proving that GA immobilizes on the MAO coating after the sample is immersed for 24 h. For O 1s, 530.9 eV belongs to aromatic C=O and magnesium oxide, while 531.7 eV is ascribed to O=C–OH and magnesium hydroxide ( Figure 4 b). Moreover, the peaks of magnesium silicate and O=C–O − (magnesium carboxylate) are very close, which are 532.8 eV and 532.4 eV, respectively; 533.5 eV is assigned to the hydroxyl group and carboxyl group, and the targeted oxygen is different from the 531.7 eV peak of GA [ 27 ]. In the oxygen spectra of the MAO group, the data showed that the coating consisted mostly of magnesium oxide and magnesium silicate, which was agrees well with the EDX and XRD data.…”

“…For Mg 2p, the peak of magnesium hydroxide is at 49.7 eV. The peak at 50.5 eV can be attributed to chelated magnesium and magnesium oxide ( Figure 4 c); 51.6 eV is the magnesium ions, which belongs to magnesium carboxylate [ 27 , 28 ]. In the magnesium spectra, after the modification of GA, the magnesium hydroxide was replaced by chelated magnesium ions as the primary peak, which meant that magnesium hydroxide underwent the condensation process and the GA complex layer preserved the source of magnesium ions [ 29 ].…”

“…In contrast, for the MAO+GA sample, not only was its corrosion resistance enhanced, but also the phenomenon of pitting corrosion disappeared. This implies that GA built a barrier to prevent the chloride ions from invading, and captured the magnesium ions to form magnesium carboxylates to buffer against pitting corrosion [ 27 ]. Moreover, it was difficult to immobilize molecules onto the magnesium or the protective coating surface in aqueous solution because of the concurrent corrosion.…”