6 research outputs found
Inverse Pickering Emulsions with Droplet Sizes below 500 nm
Inverse Pickering emulsions with
droplet diameters between 180
and 450 nm, a narrow droplet size distribution, and an outstanding
stability were prepared using a miniemulsion technique. Commercially
available hydrophilic silica nanoparticles were used to stabilize
the emulsions. They were hydrophobized in situ by the adsorption of
various neutral polymeric surfactants. The influence of different
parameters, such as kind and amount of surfactant as hydrophobizing
agent, size and charge of the silica particles, and amount of water
in the dispersed phase, as well as the kind of osmotic agent (sodium
chloride and phosphate-buffered saline), on the emulsion characteristics
was investigated. The systems were characterized by dynamic light
scattering, transmission electron microscopy, cryo-scanning electron
microscopy (cryo-SEM), thermogravimetric analysis, and semiquantitative
attenuated total reflection infrared spectroscopy. Cryo-SEM shows
that some silica particles are obviously rendered hydrophilic and
form a three-dimensional network inside the droplets
Synthesis and Characterization of Dually Labeled Pickering-Type Stabilized Polymer Nanoparticles in a Downscaled Miniemulsion System
Dual fluorescently labeled polymer particles were prepared
in a
downscaled Pickering-type miniemulsion system. Stable dispersions
were obtained and the size of the hybrid particles could be varied
between ca. 180 and 430 nm. Silica nanoparticles were employed as
sole emulsifier, which were labeled by a fluorescein dye (FITC) or
(encapsulated) quantum dots, and the polymer core was labeled by a
perylene derivative. Downscaling of the Pickering-type miniemulsion
system is intriguing by itself as it allows the use of precious nanoparticles
as emulsifiers. Here, silica particles with a fluorescent core and
an overall diameter between 20 and 40 nm were prepared and employed
as stabilizer. The dual excitation and emission of both dyes was tested
by fluorescence measurements and confocal laser scanning microscopy
(cLSM)