Electrochemical behavior of polypyrrole/chitosan composite coating on Ti metal for biomedical applications

•The higher impedance response for PPy/CHI composite coating in all the potentials.•Incorporation of CHI in composite coatings enhanced mechanical strength of PPy matrix.•The protection efficiency extended up to 1.25 V and deposition of Hap. are salient features. In the present work, the corrosion resistance performance and biocompatibility of polypyrrole/chitosan (PPy/CHI) composite coated Ti was studied. The deposition of composite coating was carried out by electropolymerization method. The deposited PPy/CHI composite coatings were different in morphology, structural, surface roughness and wettability compared PPy coated Ti. The presence of composite coating was confirmed by solid 13C NMR. The PPy/CHI composite coating showed enhanced microhardness and adhesion strength compared to the PPy coating. The corrosion protection ability of PPy/CHI composite coatings at various applied potentials was analyzed by dynamic electrochemical impedance spectroscopy (DEIS), exhibited higher impedance in all the potentials compared to uncoated and PPy coated Ti. The lower corrosion current density obtained for PPy/CHI-2 composite coating from polarization studies revealed increased corrosion protection ability in SBF solution. The stability of composite coating was confirmed by immersion studies. PPy/CHI-2 composite coating immersed in SBF solution enhances hydroxyapatite (HAp) formation.