A new process for generating nanometer-scale oil droplets in water has been reported in the journal Angewandte Chemie by Japanese researchers, who have developed a technique they named MAGIQ (monodisperse nanodroplet generation in quenched hydrothermal solution).
Under standard conditions, hydrocarbons and water do not mix; however, at high temperatures and high pressures near the critical point of water, they freely mix. Quenching homogeneous solutions of dodecane and water under these conditions in the presence of a detergent produces nanoemulsions in just ten seconds.
Oil and water are not miscible but can form emulsions in which tiny droplets of one component are dispersed in the other. Milk, face creams, and printer’s ink are examples of emulsions. Nanoemulsions with droplets that have diameters in the 20 to 200 nm range have recently attracted more attention.
Emulsions are usually made by a “top-down” process.
Mixtures of water, oil, and surfactant are subjected to external forces, such as vigorous stirring, to break up larger drops into smaller ones. This becomes harder as the droplets get smaller, so this method has inherent limits. In contrast, solid nanoparticles are usually produced in a “bottom-up” process. This begins with a homogeneous solution. The dissolved molecules aggregate to make nanoparticles. This could also be a possible method to make nanodroplets. The problem is that water and oil would have to form a homogeneous solution to start from, but they are not miscible.
Shigeru Deguchi and Nao Ifuku at the Japan Agency for Marine-Earth Science and Technology in Yokosuka have now found a way around this with their new MAGIQ process. When water is heated under pressure it reaches its critical point at 374 °C and 22.1 MPa. At this point there is no longer a difference between the liquid and gas phases. The water no longer dissociates and no clusters of water molecules can form.At this point, the properties of the water are like those of an oil—the researchers used dodecane in this case—and the two can be freely mixed together. When this homogeneous solution is quenched with cold water, a very rapid phase separation occurs, resulting in extremely small droplets in less than ten seconds. Addition of a detergent stabilizes the nanoemulsion. The researchers developed an apparatus in which they can carry out their “magic” technique in a constant flow process. The cooling temperature and speed, the ratio of water to dodecane in the mixture, and the concentration of detergent determine the—very uniform—size of the droplets.
Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201301403
Shigeru Deguchi | Angewandte Chemie
Researchers uncover protein-based “cancer signature”
05.12.2016 | Universität Basel
The Nagoya Protocol Creates Disadvantages for Many Countries when Applied to Microorganisms
05.12.2016 | Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
05.12.2016 | Power and Electrical Engineering
05.12.2016 | Materials Sciences
05.12.2016 | Power and Electrical Engineering