On the stability limit of charged droplets

1989 ◽  
Vol 422 (1863) ◽  
pp. 319-328 ◽  
Keyword(s):  
Surface Tension ◽  
Particle Size ◽  
Light Scattering ◽  
Stability Limit ◽  
Prolate Spheroid ◽  
Charged Droplets ◽  
Electric Stress ◽  
The Stability ◽  
Stability Limits

Single, highly charged droplets of dioctylphthalate and sulphuric acid of radius between 1 and 10 μm are suspended in vacuum in a quadrupol trap. As the droplets evaporate their radius is monitored continuously by light scattering and their charge is determined periodically by weight balancing. The droplets break when the electric stress exceeds that of surface tension. The largest fragment remains trapped allowing a determination of the change in volume and charge. The fraction of volume and charge lost is found to be independent of particle size and sign of charge and is variable. The oil drops lose (15.0 ± 3.9)% of their charge on breakup and (2.25 ± 0.96)% of their mass. The acid droplets lose (49.4 ± 8.3)% of their charge and less than 0.1% of their mass. The acid results are compared with those from a model of field emission based upon prolate spheroid deformation and the formation of Taylor cones. For both oil and acid droplets the stability limits are in agreement with those predicted by Lord Rayleigh.

scholarly journals Development and Optimization of Alpha-Pinene-Loaded Solid Lipid Nanoparticles (SLN) Using Experimental Factorial Design and Dispersion Analysis

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2683 ◽  
Author(s):  
Aleksandra Zielińska ◽  
Nuno R. Ferreira ◽  
Alessandra Durazzo ◽  
Massimo Lucarini ◽  
Nicola Cicero ◽  
...  
Keyword(s):  
Particle Size ◽  
Light Scattering ◽  
Factorial Design ◽  
Solid Lipid Nanoparticles ◽  
Lipid Nanoparticles ◽  
Dispersion Analysis ◽  
Solid Lipid ◽  
Alpha Pinene ◽  
The Stability

The encapsulation of bicyclic monoterpene α-pinene into solid lipid nanoparticles (SLN) is reported using experimental factorial design, followed by high-end dispersion analyzer LUMiSizer®. This equipment allows the characterization of the α-pinene-loaded SLN instability phenomena (e.g., sedimentation, flotation or coagulation), as well as the determination of the velocity distribution in the centrifugal field and the particle size distribution. In this work, SLN were produced by hot high-pressure homogenization technique. The influence of the independent variables, surfactant and lipid ratio on the physicochemical properties of SLN, such as mean particle size (Z-Ave), polydispersity index (PDI) and zeta potential (ZP), was estimated using a 22-factorial design. The Z-Ave and PDI were analyzed by dynamic light scattering, while ZP measurements were recorded by electrophoretic light scattering. Based on the obtained results, the optimal SLN dispersion was composed of 1 wt.% of α-pinene, 4 wt.% of solid lipid (Imwitor® 900 K) and 2.5 wt.% of surfactant (Poloxamer 188), depicting 136.7 nm of Z-Ave, 0.170 of PDI and 0 mV of ZP. Furthermore, LUMISizer® has been successfully used in the stability analysis of α-pinene-loaded SLN.

A thermodynamic approach to mechanical stability of nanosized particles

Open Physics ◽  
2003 ◽  
Vol 1 (2) ◽  
Author(s):  
Vladimir Samsonov ◽  
Nikolay Sdobnyakov
Keyword(s):  
Surface Tension ◽  
Free Energy ◽  
Stability Condition ◽  
Mechanical Stability ◽  
Noble Gas ◽  
Stability Limit ◽  
Gas Clusters ◽  
The Stability ◽  
The Second Variation ◽  
Nonpolar Organic

AbstractThermodynamic stability conditions for nanoparticles (resulting from non-negativity of the second variation of the free energy) have been analyzed for two cases: (i) a nonvolatile nanosized particle with the size-dependent surface tension; (ii) the limiting case of larger objects when the surface tension takes its macroscopic value. It has been shown that the mechanical stability of a nanoparticle, i.e. its stability relative to the volume fluctuations, is defined by an interplay between the excess (“surface”) free energy and the volumetric elastic energy. According to the results obtained, noble gas clusters and metal nanoparticles satisfy the mechanical stability condition. At the same time, water nanodrops, as well as nanoparticles presented by nonpolar organic molecules, correspond to the stability limit. Among the investigated systems, the stability condition is not carried out for n-Pentane clusters.

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