Synthesis and Characterization of Cerium Molybdate Nanocontainers and Their Inhibitor Complexes

Authors

  • Ioannis A. Kartsonakis,

    1. Sol–Gel Laboratory, Institute of Materials Science, NCSR “Demokritos,” 153 10 Agia Paraskevi Attikis, Greece
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  • George Kordas

    Corresponding author
    1. Sol–Gel Laboratory, Institute of Materials Science, NCSR “Demokritos,” 153 10 Agia Paraskevi Attikis, Greece
      †Author to whom correspondence should be addressed. e-mail: gkordas@ims.demokritos.gr
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  • H. Du—contributing editor

  • This project was supported by European Integrated Project “MULTIPROTECT” and by FP7 Collaborative Project “MUST”. The abbreviation “MULTIPROTECT” stands for “Advanced environmentally friendly multifunctional corrosion protection by nanotechnology” (Contract N° NMP3-CT-2005-011783). The abbreviation “MUST” stands for “Multi-Level Protection of Materials for Vehicles by “SMART” Nanocontainers” (EC Grant Agreement Number NMP3-LA-2008-214261).

†Author to whom correspondence should be addressed. e-mail: gkordas@ims.demokritos.gr

Abstract

Cerium molybdate nanocontainers were synthesized using a two-step process and then loaded with 8-hydroxyquinoline (8-HQ) or with 1-H-benzotriazole-4-sulfonic acid (1-BSA). First, polystyrene (PS) nanospheres were produced using emulsion polymerization. Second, the PS spheres were coated via the sol–gel method to form a cerium molybdate layer. Finally, the nanocontainers were made by calcination of cerium molybdate coated PS nanospheres. The products were characterized by scanning electron microscopy (SEM/EDX), transmission electron microscopy, FT-infrared (FT-IR) spectroscopy, X-ray diffraction, thermogravimetric analysis (TGA), and differential thermal analysis. Moreover, nanocontainers were loaded with 8-HQ or with 1-BSA and their presence was confirmed with FT-IR. The loading of the inhibitors in the nanocontainers was estimated with TGA. The loading amount of 8-HQ was 5.22% w/w and that of 1-BSA was 16.43%. Based on the size of the nanocontainers and the assumption that they are not broken, we deduced to the amount of approximately with 1.07 × 106 molecules of 8-HQ and 2.35 × 106 molecules of 1-BSA per nanocontainer. Furthermore, release of 8-HQ or 1-BSA in corrosive environment was studied by potentiodynamic measurements for aluminum alloys 2024-T3 (AA2024-T3) and DC01 carbon steel (DC01-CS) samples, showing that the inhibitors are released from the nanocontainers, suppressing the corrosion activities. SEM photographs confirmed that the nanocontainers maintained their shape after suspension in 0.5M NaCl solution for more than 72 h. Moreover, release of 8-HQ or 1-BSA in water was studied using spectrophotometer.

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