Search results for "Emulsion"
showing 10 items of 344 documents
3D defect engineering in polymer opals
2006
The possibility to create defined structures inside a synthetic opal is a key step towards applications in optics, where control of the propagation of light inside a photonic crystal is necessary. Here we report different methods for realizing defined embedded defects in opaline structures. Monodisperse colloids are synthesized by surfactant free emulsion polymerization of the acid labile monomer t-butyl-methacrylate (tBMA). The PtBMA colloids can be filled with sensitizer and photo acid generator and it is possible to crystallize them into photosensitive polymer opals. One method for the introduction of defects is a multilayer build-up of photo-labile (filled with photo acid generator) and…
Physicochemical Properties of Copper(II) Bis(2-ethylhexyl) Sulfosuccinate Reversed Micelles
1998
Abstract Measurements of some physicochemical properties (density, viscosity, conductance, UV–vis spectra, IR spectra) of the water/copper(II) bis(2-ethylhexyl) sulfosuccinate (Cu(DEHSS) 2 )/CCl 4 microemulsions, at a fixed surfactant molal concentration ([Cu (DEHSS) 2 ] = 0.05003 mol kg −1 ), as function of the molar ratio R ( R = [water]/[DEHSS − ]) have been performed at 25°C. Information on some structural and dynamical properties of the water-containing Cu(DEHSS) 2 reversed micelles and of their evolution with R are derived from the experimental results. The comparison with the same properties of water-containing sodium bis(2-ethylhexyl) sulfosuccinate reversed micelles allows to evide…
Synthesis, Morphology and Rheological Behavior of Fluoropolymer-Polyacrylate Nanocomposites
2007
Nanocomposite materials composed of a PTFE copolymer core and an acrylic copolymer shell have been prepared by seeded emulsion polymerization. The effect of seed particle number and shell polymer composition on secondary particle nucleation and film formation ability of the dispersions has been studied. While TEM reveals a core-shell structure present in the particles, AFM investigation of the film shows a nearly uniform dispersion of the fluorinated seed particles in a matrix formed by the shell polymer. Rheological measurements show composite behavior of the core-shell latex films, especially at elevated temperatures, and an increase in viscosity and storage modulus when compared with the…
From Polymers to Nanomedicines: New Materials for Future Vaccines
2013
Nanomedicine is the medical application of nanotechnology and therefore covers various kinds of nanoparticles. In this chapter, we would like to provide a brief introduction and overview of nanoparticles for the modulation of the immune system. In general, these nano-sized objects can be inorganic colloids, organic colloids (synthesized by emulsion polymerization or mini-/nanoemulsion techniques), polymeric aggregates (micelles or polymersomes), core cross-linked aggregates (nanohydrogels, crosslinked micelles, or polyplexes), multifunctional polymer coils, dendritic polymers or perfect dendrimers. A special focus is set on polymeric materials, because the chemical composition of the partic…
Electrical conductivity and permittivity of water-AOT-n-heptane microemulsions
1995
Measurements of the electrical conductivity and of the complex permittivity of water-sodium bis(2-ethylhexyl) sulfosuccinate (AOT)-n-heptane microemulsions are reported. The experimental results are rationalized in terms of a hopping mechanism of AOT anions within clusters of reversed micelles. The dependence of the hopping rate and of the cluster dimensions upon the ratio [water]/[AOT] and temperature is discussed.
Photosensitive functionalized surface-modified quantum dots for polymeric structures via two-photon-initiated polymerization technique.
2015
In this paper, the surface modification of CdSe- and CdZnS-based quantum dots (QDs) with a functional silica shell is reported. Functionalized silica shells are prepared by two routes: either by ligand exchange and a modified Stober process or by a miniemulsion process with amphiphilic poly(oxyethylene) nonylphenylether also know as Igepal CO-520 (IG) as oligomeric amphiphile and modified silica precursors. The polymerizable groups on the functionalized silica shell allow covalent bonding to a polymer matrix and prevent demixing during polymerization and crosslinking. This allows the homogeneous incorporation of QDs in a crosslinked polymer matrix. This paper furthermore demonstrates that t…
PolyAT chemical denaturation in w/o microemulsion
2004
CD and UV spectroscopies have been used to investigate the effects caused by the addition of either strong acid-or base-containing microemulsions on the behaviour of the synthetic polynucleotide polyAT entrapped in the aqueous core of a cationic quaternary water-in-oil microemulsion (μE). The titrations were performed in the presence of variable concentrations of NaCl, in the range 0.00 to 0.60 M. In both cases, the primary effect was the reversible transition from B-double helix to random coil of the guest polynucleotide. However, in the microemulsive medium, the number of moles of protons (RH) and hydroxide ions (ROH) per mole of titrable sites are independent of the salt concentration bu…
Nonionic Maleic Surfmers
2002
ABSTRACT A set of nonionic maleic surfactants have been prepared, all coming from the derivatization of maleic hemiesters with a long alkyl chain. They are either amidoesters or diester products. In the case of amidoesters, the acid group was first activated and then reacted with primary or secondary or tertiary ethanolamine compounds. In the case of diesters, the hemiester was reacted directly with glycidol, in acid or basic conditions. These surfactants were characterized for their structure by 1H NMR, and for their surface active properties, by surface tension measurements. They were also used in batch emulsion polymerisation of styrene, and seeded core-shell copolymerisation of a 1/1 mi…
Reactions of Maleisomides with Alcohols
2004
Abstract New surfactants (surfmers) with various amide and ester groups next to C˭C double bonds have been obtained. Maleic acid amidesters (AE) with different hydrophobic groups at the nitrogen atom and hydrophilic substituents at oxygen atoms were synthesized starting with maleic isoimides. 1H KMR and IR spectra were used for their characterization. Some were further characterized for their critical micellar concentration (CMC). A few cationic and zwitterionic surfmers were also prepared from isoimide precursors and characterized. All these surfmers were applied in batch emulsion polymerization of styrene, and in core‐shell seeded copolymerization of styrene and butylacrylate to give late…
Surface-Functionalized Latex Particles as Controlling Agents for the Mineralization of Zinc Oxide in Aqueous Medium
2005
Polystyrene latex particles modified at the surface with different hydrophilic functional groups were prepared by miniemulsion polymerization and used as controlling agents in the crystallization of zinc oxide from aqueous medium. The effects of the chemical nature of the surface functionalization and the latex concentration on the crystal growth, morphology, and crystalline structure of the resulting zinc oxide were analyzed. Micro- and submicrosized crystals with a broad variety of morphologies depending on the functionalization were obtained. Among the different latexes studied, the acrylic-acid-derived particles were shown to be a convenient system for further quantitative investigation…