Enhancing the biodegradability and surface protective performance of AZ31 Mg alloy using polypyrrole/gelatin composite coatings with anodized Mg surface

Preparation and Corrosion Performance of PPy/Silane Film on AZ31 Magnesium Alloy via One-Step Cyclic Voltammetry

“…The peaks at 1455 cm −1 and 1581 cm −1 are attributed to the absorption peaks of the C=C stretching vibration of the pyrrole ring skeleton. The stretching vibration peak of N–H is detected around 3400 cm −1 [ 6 , 18 ]. The characteristic peaks of Si–OH formed after hydrolysis are found at 3200 cm −1 ~3380 cm −1 because some Si–OH had no condensation reaction of dehalohydrination or dehydration with other Si–OH or metal substrate during the electro-polymerization and curing process [ 19 ].…”

“…Many types of them have been researched, such as chemical conversion coating, anodic oxide film, laser surface treatment and organic coating [ 1 , 2 , 3 , 4 ]. Recently, conducting polymers (CPs) such as polyaniline (PANI) [ 5 ], polypyrrole (PPy) [ 6 ] and polythiophene (PTh) [ 7 ] have become the research hotspot in organic coatings on the Mg alloy. Among the various kinds of conductive polymers, PPy has been used to improve the corrosion resistance of metal [ 8 , 9 , 10 ].…”

A Comprehensive Review on Surface Modifications of Biodegradable Magnesium-Based Implant Alloy: Polymer Coatings Opportunities and Challenges

“…As a result of its biological origin, biocompatibility, immunogenicity, and bioactivity, gelatin (Gel), a collagen derivative, has recently been used in a wide range of biomedical applications, including drug delivery, tissue engineering, wound bands, and medical care devices. Additionally, gelatin enhances the adhesion, migration, and proliferation of a wide variety of cells [85]. Jafarzadeh et al [86] used the dip-coating technique to deposit a gelatin/Si−Mg−FA nanocomposite coating on AZ31 Mg alloy specimens.…”

“…As opposed to the uncoated specimen, the formation of an anodized and nanocomposite coating results in a change in E corr to more positive values (−1.68 to −1.47 V), while the corrosion current densities of the coated specimens are moved to a smaller amount (2.98 × 10 −4 to 5.022 × 10 −5 A•cm −2 ) compared to the uncoated counterpart, implying that the composite coating could regulate the corrosion rate of Mg alloys for orthopedic applications. Jothi et al [85] fabricated polypyrrole/Gel coatings using anodization and electrodeposition methods to increase the corrosion resistance of AZ31 Mg substrates. The influence of anodization time and gelatin content on the corrosion resistance efficiency of coated AZ31 Mg substrates was thoroughly investigated via various characterization approaches.…”

“…Surface and structural characterization tests were used to validate the influence of anodization period and gelatin inclusion on the surface characteristics of polymeric films on Mg substrates. In vitro corrosion test results confirmed that the R ct value of polypyrrole/gelatin 1 wt % (PPy/Gel2) (6.74 × 10 5 Ω•cm 2 ) is four times that of pure PPy-40 min anodization time (1.91 × 10 5 Ω•cm 2 ) and one order of magnitude higher than that of neat PPy (2.31 × 10 4 Ω•cm 2 ), suggesting that the anodized AZ31 Mg substrate with coating portrayed the greatest surface protective employment toward corrosion [85]. Based on scanning electrochemical microscopy (SECM), the level of hydrogen released is considerably diminished in the existence of an anodization layer prior to coating and gel inclusion into the PPy coating.…”