Table 1.

Characteristics and effects of synthetic polymer coatings on Mg-based alloys.

Polymer	Polymer Properties	Coating	Mg-Based Substrate	Coating Technology	Remarks	Ref.
Polylactic Acid (PLA)	Biodegradable, Young’s modulus of about 3 GPa, ultimate tensile strength (UTS) of 50–70 MPa, fracture toughness of about 2.5 kJ/m2, biocompatible, degrades through hydrolysis	Poly(L-lactic acid) (PLLA)	Pure Mg rods	Dip-coating	PLLA coatings with porous structures and dense surfaces were obtained. The corrosion resistance was improved, and the lower pH of the coating sustained the emission of Mg2+ ions	[30]
		PLA	Mg-9Al-1Zn (AZ91)	Spin-coating	PLA coating improved the corrosion behavior of the Mg-based alloy	[29]
Poly(Lactide-Co-Glycolic) Acid (PLGA)	High biocompatibility, already approved for use in human clinical trials, biodegradability, exhibits controllable degradation properties	PLGA	Mg-6Zn	Dip-coating	The degradation rate was reduced by a high amount	[31]
Polycapro lactone (PCL)	PCL is Food and Drug Administration (FDA)-approved. Biocompatibiliy, biodegradability, nontoxicity, high strain failure rate	PCL	Mg-based scaffolds produced through powder metallurgy route	Dip-coating	The degradation rate was reduced	[33]
		PCL	Mg-6%Zn-10%Ca3(PO4)2 scaffolds	Surface sprayed and solidified at 50 °C for 5 min	Corrosion activity, surface morphology, and cytotoxicity were improved	[32]
Cellulose acetate (CA)	It increases corrosion resistance. CA is a thermoplastic material, and its main source is cellulose that is a natural polymer. CA is not manufactured by polymerization of any monomer	CA	Mg-Ca-Mn-Zr	Dip-coating	The coating increased the corrosion resistance. The material exhibited good cytocompatibility, promoting cell adhesion, viability, proliferation, and osteogenic differentiation	[34]