Rheology and silver nanoparticle templating in a bis(urea) silver metallogel

A new bis(urea) ligand comprising three pyridyl groups exhibits strong gelation with silver tetrafluoroborate in THF/water mixtures. Upon standing silver nanoparticles grow in the gel. TEM confirms that the particles are exclusively formed in the gel fibres. The rate of formation of nanosized silver can be increased by illuminating the gel with UV radiation (365 nm). The metallogel and gel-nanoparticle composite rheology is complex with the presence of the nanoparticles strengthening the gel considerably in some cases, and dependent on the concentration of silver(I).