Smart release of turmeric as a potential corrosion inhibitor from a pH-responsive polymer encapsulated highly ordered mesoporous silica containers
Durgambika Venkatachalam, Yoganandan Govindaraj, J. Manoj Prabhakar, Arulkumar Ganapathi, Masatoshi Sakairi, Michael Rohwerder, Lakshman Neelakantan
Abstract
This study reports on the loading of corrosion inhibitors like benzotriazole (organic), tartrazine , and turmeric (green) into highly ordered mesoporous silica containers encapsulated with a pH-responsive polymer poly(diallyldimethylammonium chloride) (PDDA) for the smart and sustained release. The incorporation and encapsulation of green corrosion inhibitors , release kinetics and its inhibition efficiency is not studied yet. The synthesised containers had a mesoporous micro-rod-like structure with a pore size of 7 nm and a high surface area of 514.26 m 2 /g. The pH-responsive behaviour of the PDDA encapsulating polymer is confirmed by monitoring the release of the inhibitors in neutral and alkaline solutions using UV–Visible spectroscopy. The corrosion inhibition performance and its mechanism are evaluated in an alkaline environment containing 0.1 M NaCl using electrochemical impedance spectroscopy over a period of 168 h on mild steel. Among the studied corrosion inhibitors, turmeric showed a maximum of 85.4 % inhibition efficiency after 1 h of immersion. However, SBA-15-Turmeric-PDDA exhibited a higher R p value of 0.96 kΩ cm 2 compared to only turmeric after 168 h of exposure. The smart release of turmeric and silica adsorption showed enhanced corrosion protection , which can be used for various industrial applications.