Stable Dispersions of Aromatic Hydrocarbon Colloidal Particles by Laser Ablation

Dispersions of colloidal particles of polycyclic aromatic hydrocarbons were obtained by
nanosecond laser ablation. Aqueous suspensions of micron-sized crystals were irradiated with the
second harmonic output of a Nd:YAG laser and converted into colloidal particles. Ionic and nonionic
surfactants were used in the ablation process to stabilise the particles. Dispersions with good
long term stability were obtained. A strong dependence of particle formation rate on laser fluence
was found and the particle formation process is discussed on the basis of UV-Vis spectra and
microscopic examination of the crystals.