Trapping metal nanoclusters in "soap and water" soft crystals.

Experimental Section Cross-polarised optical microscopy was performed using an Olympus BH-2 microscope coupled to a Leica DM-IRB digital camera. The gel samples were sealed two glass plates using vacuum grease to enable aging observations. Small angle X-ray scattering (SAXS) experiments were performed using a rotating anode with a copper target (λ = 1.54 Å). The distance between the sample and the detector was fixed at 1.16 m, the scattering wave vectors ranging between 0.5 nm and 10 nm, the instrument width being approximately 5×10 nm. The samples were placed between two 30 μm mica sheets spaced by a glass object plate (1 mm thickness) with a window in its center and sealed with vacuum grease. X-ray exposure time was 1 h. Centrifuging was performed at 200 g using an Eppendorf 5412 centrifuge. Unless noted otherwise, chemicals were purchased from commercial firms (>99% pure) and used as received. Triple-distilled water was used in all experiments.