Silver nanoparticles of variable morphology synthesized in aqueous foams as novel templates

In this paper, we describe the synthesis of si lver nanocrystals within aqueous foams as a template. More specifically, we show that aqueous Ag + ions may be electrostatic ally complexed with the anionic surfa c- tants aerosol OT (sodium bis-2-ethylhexyl-sulfosuccinate, (AOT) and sodium dodecyl sulphate (SDS)) in a highly stable liquid foam. After drainage of the foam, the silver ions are reduced in situ by introducing sodium borohydride into the foam by capillary flow. This leads to the formation of silver nano particles of spherical, tape- and sheet-like morphology in the foam. The structure of the foam is extremely complex and presents rea ction sites of different spatial extent. The differences in foam reaction -site geometry are believed to be responsible for the morphology variation in the silver nanoparticles observed. The si lver nanoparticles are observed to be extremely stable in solution suggesting that the AOT or SDS molecules stabilize them. This a pproach appears promising for application in large -scale synthesis of nanoparticles and may be readily extended to other chemical compositions.