The method of formation of nanoparticle aggregates such as high-coverage spherical shells of microspheres or 3-D micro crystals grown in the geometry unaffected by a substrate is described. In the reported experiment, the evaporation of single levitated water droplet containing 200 nm diameter polystyrene spheres was studied. Successive stages of the drying process were discussed by analyzing the intensity of light elastically scattered by the evaporating droplet. The numerically simulated self-assembly coincides nicely with the observed morphologies resulting from transformation of a droplet of suspension into a solid microcrystal via kinetically driven self-assembly of nanostructures.

The range of applicability of a fundamental tool for studying the evolution of droplets, the radius-square-law, was investigated both analytically and numerically, on the basis of the experimental results of our own as well as of other authors. Standard issues were briey discussed. Departures from the radius-square-law caused by the inuence of impurities encountered in non-ideal liquids, by the kinetic and surface tension eects encountered for small droplets or by thermal imbalance encountered in light-absorbing droplets were analysed. The entanglement between the kinetic and impurities eects was studied numerically yielding a possible explanation to evaporation coecient discrepancies found in the literature.An unexpected radius-square-law persistence in case of non-isothermal evolutions of very small droplets in atmosphere nearly saturated with vapour was analysed. The coexistence of the kinetic eects and the strong eects of surface tension was found responsible for this eect.

Evaporation of motionless, levitating droplets of pure, low-volatility liquids was studied with interferometric methods. Experiments were conducted on charged droplets in the electrodynamic trap in nitrogen at atmospheric pressure at 298 K. Mono-, di-, tri-, and tetra(ethylene glycols) and 1,3-dimethyl-2-imidazolidinone were studied. The influence of minute impurities (<0.1%) upon the process of droplet evaporation was observed and discussed. The gas phase diffusion and evaporation coefficients were found from droplet radii evolution under the assumption of known vapor pressure. Diffusion coefficients were compared with independent measurements and calculations (in air). Good agreement was found for mono- and di(ethylene glycols), and for 1,3-dimethyl-2-imidazolidinone, which confirmed the used vapor pressure values. The value of equilibrium vapor pressure for tri(ethylene glycol) was proposed to be 0.044 +/- 0.008 Pa. The evaporation coefficient was found to increase from 0.035 to 0.16 versus the molecular mass of the compound.

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