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
Newly designed molecule binds nitrogen
23.02.2018 | Julius-Maximilians-Universität Würzburg
Atomic Design by Water
23.02.2018 | Max-Planck-Institut für Eisenforschung GmbH
A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.
In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...
A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.
By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...
Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
23.02.2018 | Physics and Astronomy
23.02.2018 | Health and Medicine
23.02.2018 | Physics and Astronomy