Products: complex micro and nanoparticles

Our proprietary technology is being used in combination with a variety of materials for different technological applications. Some types of complex micro and nanoparticles the YFLOW manufactures, as well as some processes, are briefly described here.

Complex particles
Micro and nano hollow capsules.
Production of food grade micro capsules.
Micro and nano spheres.
Dispersion of nanoparticles (thin coatings).
Hollow nanofibers.
Coaxial nanofibers.

Processes

Electrified coaxial jets.
Electrospray in liquid baths. Generation of micro/nanoemulsions.
Simple and Coaxial electrospinning (co-electrospinning).
Electrospray Multiplexing.

Micro and nano hollow capsules.
       The hollow capsules are formed from a coaxial electrified jet of a sol-gel formulation (outside liquid) and a regular non-structured liquid inside (inner liquid). The jet break up give rise to charged liquid capsules. In-flight evaporation of the solvent from the outer liquid promoted gelation (solidification) of the capsule outer shell. After collection, the inner liquid is solvent extracted.
 

                                                   

 Production of food grade micro capsules.
         The pictures show capsules in which the shell is a non-aqueous polymer encapsulating an aqueous solution (left) and an aqueous based polymer encapsulating  a non-aqueous solution (right) one. At the bottom, the set of pictures show the aqueous (inner) component of a bunch of partially melted and coagulated capsules.

 Micro and Nano spheres.
         Electro-hydro-dynamic dispersion of liquid solutions or melts allows generating micro and nanoparticles of controlled sized. In the example shown, a solution of a carbonaceous component is finely dispersed to produce micron and submicron spheres.

 Dispersion of Nanoparticles (thin coatings).
         When the liquid to be dispersed is a suspension of nanoparticles, the adjustment of suspension stability and particle concentration allows to finely dispersing the nanoparticles. Since all of the nanoparticles bear the same charge, in-flight agglomeration is completely avoided. The coatings may exhibit a highly open fractal structure, as shown in the examples.

Hollow Nanofibers.
         Similarly as in the previous co-electrospinning, if the inner liquid is a regular, non-structured liquid and if solidification of the outer melt occurs fast enough to prevent varicose instabilities to grow, the process leads to the production of hollow nanofibers (nanotubes) in one step..

Coaxial Nanofibers.
         Similarly as in the classical electrospinning process, when two polymer melts instead of one are used to form the electrified coaxial jet (the so called co-electrospinning), the highly effective electric stretching of the coaxial jet leads to the formation of coaxial nanofibers..

                       

Electrified coaxial jets.
         This is the core of YFLOW technology. It consists on the formation of a very thin coaxial jet of immiscible liquids by the action of the electro-hydro-dynamic (EHD) forces. The two liquids are injected through two coaxial needles connected to a high voltage power supply. At the needles exit, the action of the electric field causes the compound meniscus to adopt a conical shape (so called compound Taylor cone), from whose apex a very thin coaxial jet is issued. The diameter of this coaxial jet is independent of that of the needles, and can be tailored into the micro or nanometric size range by suitably tuning the liquids properties. The fait of this coaxial micro or nanojet may lead to the formation of micro/nanocapsules or micro/nanofibers with well defined core-shell structure.

Electrosprays in liquid baths.
         The EHD processes (electrospray, electrospinning, electrified coaxial jets) can also take place inside insulating liquid baths. The technique may be of interest in obtaining fine liquid-liquid emulsions of uniformly sized droplets in the nanometric range, as well on dispersing in water phase highly hydrophobic liquids (Pictures by A. G. Mar