Development of chitosan and sodium alginate composite coating on 316l stainless steel by electrochemical method

Abstract

Stainless steel has been used as material for orthopedic and orthodontic implants due to their low cost, good formability and proper mechanical properties. However, stainless steel is susceptible to pitting corrosion in body fluids and have poor wear resistance which limits its applications. Surface coating with certain ceramic and polymer composites are done to improve the biocompatibility of stainless steel. Chitosan is the cationic regular biopolymer having a unique structure, multidimensional properties, highly sophisticated function and extensive variety of requisition in biomedical field. Chitosan is a promising biomaterial for medical implants due to its biocompatibility, biodegradability and nontoxic property alongside its antimicrobial action and low immunogenicity. A chitosan and chitosan-sodium alginate composite layer has been electrophoreticaly deposited on 316L stainless steel. The solution comprises of distilled water and acetic acid. The deposition of chitosan and sodium alginate was carried out for 5, 10, 15 and 20 min at constant power supply of 20V on the cathode. The morphological analysis using optical microscopy, phase purity analysis using X-ray diffraction (XRD), molecular structure analysis using Fourier transform infrared spectroscopy (FTIR) and wettability by sessile drop method was done to characterize the samples. FTIR indicated the existence of bond between protonated carboxylate bonds and partially protonated amine group which will enhance the protein adhesion on the coated surface.