Observation of a crossover in kinetic aggregation of Palladium colloids

摘要: Abstract We use field emission scanning electron microscope (FE-SEM) to investigate the growth of palladium colloids over surface thin films WO 3 /glass. The film is prepared by Pulsed Laser Deposition (PLD) at different temperatures. A PdCl 2 (aq) droplet injected on and in presence steam hydrogen dried through a reduction reaction process. Two distinct aggregation regimes are observed substrates. argue that change dynamics emerges when measured water drop Contact Angel (CA) for /glass passes certain threshold value, namely CA ≈ 46°, where crossover kinetic occurs. Our results suggest mass fractal dimension aggregates follows power-law behavior. ( D f ) fast regime, CA values vary from 27° up 46° according substrate deposition temperatures,  = 1.75(± 0.02) – value excellent agreement with other colloidal systems regime. Whereas slow CA = 58°, changes abruptly  = 1.92(± 0.03). have also used modified Box-Counting method calculate gray-level images observe around CA ≈ 46° remains unchanged.