In Situ Self-Assembly of Silver Nanoparticles

We have found that the thermal decomposition of [Ag-(O2CHnH2n-1)](2), where n = 14, 16, 18, and 22, produces the ordered 3D nanostructure (supracrystals) directly during the chemical reaction, which makes it possible to obtain self-assembled structures in large quantities without requiring additional processing steps. The process of self-assembling of silver nanoparticles is characterized by TEM and in situ time-resolved SAXRD and WAXS data. The calculated unit-cell parameters of the fcc nanostructures formed correlate with the aliphatic chain length: these are 9.55 nm for silver myristate (n = 14), 9.8 nm for silver palmitate (n = 16), 10.46 nm for silver stearate (n = 18), and 12.5 nm for silver behenate (n = 22). Structural and morphological characteristics of supracrystals formed in situ during the thermal decomposition of silver carboxylates are found to be dependent on the sample heating rate. The self-assembled ordering of the silver nanoparticles was observed to begin at similar to 180, and above similar to 280 degrees C the supracrystalline structures begin to decompose.