On the formation of nanocapsules in aerosol‐assisted atmospheric‐pressure plasma

Abstract

Aerosol-assisted atmospheric-pressure plasma can lead to the deposition of very appealing core-shell structured nanocapsules. In this work, the aerosol solution composition has been changed in terms of solute nature and concentration in order to better understand the nanocapsule formation and structure. In particular,

Hierarchical Structures Formed in an Atmospheric Pressure Plasma Jet by Polymerization from an Aerosol of Oxalic Acid Stabilized WO3–x Nanosheet Colloids: Toward High-Performance Electrochemical Devices and Sensors

“…On top of the effects of droplet evaporation, particle diffusion, and crystallization of the organic and inorganic components, an additional effect in our work is that of plasma-induced reactions of both the inorganic and organic components of the colloid. The formation of nanocapsule structures from plasma-induced modification of aerosol droplets has been previously reported by Lo Porto and co-workers . Nanocapsule formation is attributed to a three-step process in which the first two steps are equivalent to conventional aerosol drying and consist of a uniform droplet evaporation step followed by the precipitation and aggregation of solute particles within the droplet.…”

“…The formation of nanocapsule structures from plasma-induced modification of aerosol droplets has been previously reported by Lo Porto and co-workers. 46 Nanocapsule formation is attributed to a threestep process in which the first two steps are equivalent to conventional aerosol drying and consist of a uniform droplet evaporation step followed by the precipitation and aggregation of solute particles within the droplet. Localization of material at the droplet surface (crust formation) occurs when the Peclet number is high; that is, the diffusion rate of the solute particles dispersed in the droplet is low.…”

Recent Advancements in the Use of Aerosol-Assisted Atmospheric Pressure Plasma Deposition

“…More interestingly, after water immersion for 1h, the spherical features become empty or collapse (Figure 15c). For this reason, but also thanks to further observation by confocal fluorescence microscopy [73], and a more systematic investigation carried out on aerosol solutions fed with compounds possessing different chemical properties [75], it was demonstrated that the spheres had a nanocapsule structure. Such nanocapsules consist of a core made of the solute of the nebulized droplets and a shell formed by the precursor added in the feed-in this case, ethylene.…”

“…Here, an interesting chapter of the story is revealed, and a more detailed discussion can be found elsewhere [114], regarding the formation-in certain cases-of such spherical structures when a solution is atomized in atmospheric pressure plasma. In fact, besides the mentioned papers on lysozymes and BSA, spherical nanostructures were found for vancomycin and gentamicin nanocomposite coatings [63,[72][73][74][75] during studies on the deposition of antibiotic delivery systems. On the one hand, these papers show that the drugs retain their antibacterial activity once embedded in a plasma polymerized film and gradually released in the aqueous medium.…”

“…P e = K/D, where D is the mass diffusivity of the particle/solute dispersed in the solvent, and K is the evaporation rate (supposed constant). Reprinted with permission from[75]. Copyright 2006 John Wiley & Sons, Inc.…”