Texas A&M University-Corpus Christi, United States
pp. 494 - 497
Keywords: hydrophillic, hydrophobic, cavity, evaporation, plasmon
Innovative optical techniques based on nano-biophotonics such as surface plasmon resonance (SPR) imaging are developed to characterize the transport and optical properties of nanofluids in situ, real-time, and full field manner. Al2O3 nanofluids (47 nm in water) droplets are placed on substrates and evaporated in room temperature. Simultaneous surface Plasmon resonance imaging and natural fringe mapping techniques are employed to characterize solid-liquid-vapor phases of nanofluids during self assembly process in real-time and full-field manner. The existence of hidden complex cavities formed inside a self-assembled nanocrystalline structure is discovered in real-time. Interference fringes allowed us to reconstruct the 3D cavity formation and crystallization processes quantitatively. The formation of the complex inner structure was found to be attributable to multiple cavity inceptions and their competing growth during the aquatic evaporation. Additionally, the effect of surface hydrophobicity is examined in the formation of hidden complex cavities during the evaporation-induced nanocrystalline self-assembly, taking place on three different substrates bearing different levels of hydrophobicity; namely, cover glass (CG), gold thin film (Au), and polystyrene dish (PS). These surface plamson resonance imaging and natural fringe mapping techniques are expected to provide substantial tools to characterize nano-bio materials and their interaction phenomena.