Synthesis of L-leucine nanoparticles via physical vapor deposition at varying saturation conditions

Janne Raula, Annukka Kuivanen, Anna Lähde, Hua Jiang, Maxim Antopolsky, Jarno Kansikas, Esko I. Kauppinen

Research output: Contribution to journalArticleScientificpeer-review

28 Citations (Scopus)


Preparation of -leucine nanoparticles by a process based on physical vapor deposition has been presented. In an aerosol flow reactor method, aqueous -leucine droplets were first dried followed by the sublimation of -leucine to produce vapor that upon vapor deposition resulted in -leucine nanoparticles with size ranging from 40 to 200 nm. Onset temperature for the sublimation of -leucine at concentrations from 0.02 to increased from 135 to , respectively.
The formation of nanoparticles was initiated in three different ways: (i) via droplet drying, (ii) via heterogeneous nucleation of -leucine vapor on solid -leucine particles, and (iii) via homogeneous nucleation of -leucine vapor to form new-born nanoparticles. Consequently, the saturation conditions of -leucine vapor in the reactor determined the resulting particle size, size distribution and number concentration, those depending very much on nucleation mode.
In general, the both nucleation modes produced narrow size distributions, that is, geometric standard deviation (GSD) was although the number concentration increased with the increased amount of -leucine vapor.
Upon desublimation and vapor deposition, -leucine formed leafy crystals whose size was the largest when produced from the heated section at the vicinity of the onset temperature and the smallest far above the onset temperature.
All the particles prepared in the conditions (i)–(iii) were crystalline. However, X-ray diffraction analysis showed preferential direction for crystal growth according to the way of particle formation.
Original languageEnglish
Pages (from-to)1172-1184
JournalJournal of Aerosol Science
Issue number12
Publication statusPublished - 2007
MoE publication typeA1 Journal article-refereed


  • L-leucine
  • nanoparticles
  • physical vapor deposition


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