Large scale synthesis of ordered silver nanoparticles for superhydrophobic and anti-icing application

摘要

An optimized reduction of silver ions in presence of ethylene glycol (EG) and polyvinylpyrrolidone (PVP) produced colloidal silver nanoparticles in the solution. This colloidal solution has been spin-coated on glass substrates, annealed, and finally coated with thin films of polytetrafluoroethylene (PTFE) by plasma sputtering. AFM studies show that the size of the as-deposited silver nanoparticles is ～60 nm and it increases with the duration of annealing. However, UV-Vis investigation reveals that particle size initially increases with the time of annealing then starts reducing. This contradictory observation is due to the oxidation of silver and the present investigation confirms that the larger particles seen on AFM images are actually silver oxides rather than silver per se. Silver nanoparticles annealed at different duration were coated with PTFE. The resulting samples showed a decrease in hydrophobicity with annealing time. This observation is explained by assuming that the spherical silver nanoparticles are partially embedded onto the smooth surface used as substrate.