Effect of Temperature and Humidity on Coarsening Behavior of Au Nanoparticles Embedded in Liquid Crystalline Lipid Membrane

摘要

Coarsening behavior of the Au nanoparticles produced bynthermal evaporation of Au onto a liquid crystalline lipid (1,2-dioleoyl-3-ntrimethylammonium-propane, DOTAP) membrane was investigated bynsubjecting the nanoparticle-embedded DOTAP membrane to twondifferent annealing conditions (at 100 °C under no humidity and at 20n°C and 80% relative humidity). Although the coarsening rate wasnrelatively slow because of the low temperature (from 5.6 nm in the asdepositednstate to ∼7 nm after 30 h), it was identified that at 100 °Cnwithout humidity the Au nanoparticles resulted in shape refinementnwhereas the high humidity at 20 °C induced self-organization of thennanoparticles into a monolayer. It was also found that annealing in bothncases tended to segregate the lipid molecules from the nanoparticle array and forced the nanoparticles into a tighter area. In thencase of the high-humidity sample, the lipid segregation eventually led to extensive coalescence of the Au nanoparticles.