8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Fri 911:10-14:00P6.25Effect of foreign adsorbable gases on phase transitionson surface of nanoscale objectsValeri Levdansky, 1 Jiri Smolik, 1 and Vladimir Zdimal 11 Institute of Chemical Process Fundamentals AS CR, v. v. i. , Rozvojova 135,165 02 Prague, Czech Republic, 165 02, Prague, Czech RepublicIn recent years, increasing attention of researchers has been given to transfer phenomena withphase transitions in the systems with nanoscale objects. This is related in particular to manufactureof nanoparticles and nanowhiskers, drying of materials with nanoscale pores and so on. Here theproblems related to the effect of foreign adsorbable gases on phase transitions on the nanoparticlesurface as well as on the surface of a liquid meniscus in the nanoscale capillary are studied theoretically.The presence of adsorbed molecules of a foreign gas on the curved interface, where theKelvin correction to the saturated vapor pressure is essential, influences phase transitions on thesurface of nanoscale objects in two ways. On the one hand, adsorption of molecules of a foreigngas on the nanoscale object leads to a blocking effect in relation to phase transitions on the surfaceof the object that decreases the flux densities of both the evaporating and condensing molecules.On the other hand, adsorbed molecules can decrease the surface tension that leads to a decreasein the flux density of molecules evaporating from the aerosol nanoparticle and to an increase inthe above-mentioned flux density in the case of molecule evaporation from a concave nanoscalemeniscus. It is shown that, depending on the value of the saturation ratio, the presence of an adsorbableforeign gas in the system can lead both to a decrease and to an increase in the resultingflux of vapor molecules outgoing from the nanoscale capillary in the case of molecule evaporationfrom the concave meniscus. The similar situation takes place in relation to the growth rate ofthe aerosol nanoparticle by vapor condensation. This work was supported by GAAVCR projectsIAA400720804, IAA200760905 and GACR project 101/09/1633.25