Encapsulation and release of corrosion inhibitors into titania nanocontainers

Titania nanocontainers were synthesized through a two-step process and then loaded with 8-hydroxyquinoline (8-HQ) and p-toluenesulfonic acid (p-TSA). The size of the containers was 242 +/- 10 nm as determined by Scanning Electron Microscopy (SEM). X-Ray Diffraction Analysis (XRD) showed that the titania nanocontainers consist of anatase and rutile crystalline phases. The presence of 8-HQ and p-TSA in the nanocontainers was confirmed with Fourier Transform Infrared Spectroscopy (FT-IR). The loading of the inhibitors in the nanocontainers was estimated with Thermo Gravimetric Analysis (TGA). The loading amount of 8-HQ is 3.56% w/w and that of p-TSA is 6.13%. Based on the size of the nanocontainers and the assumption that they are not broken, the amount of approximately with 2.83 x 10(6) molecules of 8-HQ and 3.86 x 10(6) molecules of p-TSA per nanocontainer was estimated. Furthermore, release studies of 8-HQ and p-TSA in a corrosive environment were studied by potentiodynamic measurements showing that the inhibitors are released from the nanocontainers, suppressing the corrosion activities. SEM and Dynamic Light Scattering (DLS) measurements confirmed that the nanocontainers are not agglomerated and keep their shape after suspension in 0.5 M NaCI solution for more than 72 hours.