Development of multifunctional polydimethylsiloxane (PDMS)-epoxy-zinc oxide nanocomposite coatings for marine applications

Multifunctional epoxy-polydimethylsiloxane nanocomposite coatings with antifouling and anticorrosion characteristics have been developed via in situ polymerization method at different loading (1, 3, and 6.5 wt.%) of ZnO nanoparticles to cater marine applications. A detailed comparative analysis has been carried out between epoxy-polydimethylsiloxane control (EPC) and ZnO-reinforced coatings to determine the influence of ZnO loading on various properties. The incorporation of ZnO in EPC led to increase in root mean square (RMS) roughness to 126.75 nm and improved hydrophobicity showing maximum contact angle of 123.5 degrees with low surface energy of 19.75 mN/m of nanocomposite coating as compared with control coating. The differential scanning calorimetry (DSC) result indicated improved glass transition temperature of nanocomposite coatings with highest T-g obtained at 83.69 degrees C in case of 1 wt.% loading of ZnO. The increase in hydrophobicity of the system was accompanied by upgraded anticorrosion performance exhibiting 98.8% corrosion inhibition efficiency (CIE) as compared with control coating and lower corrosion rate of 0.12 x 10(-3) mm/year. The Taber abrasion resistance and pull-off adhesion strength results indicated an increment of 34.7% and 150.7%, respectively, in case of nanocomposite coating as compared with the control coating. The hardness of nanocomposite coatings was also improved, and maximum hardness was found to be 65.75 MPa for nanocomposite coating with 1 wt.% of ZnO. Our study showed that the nanocomposite coating was efficient in inhibiting accumulation of marine bacteria and preventing biofouling for more than 8 months. The developed environment-friendly and efficient nanocomposite material has a promising future as a high-performance anticorrosive and antifouling coating for marine applications.