Max Planck researchers elucidate how the phase state of aerosol nanoparticles depends on their size
Whether tiny particles in the air, so-called aerosol nanoparticles, are solid or liquid, is of great importance to atmospheric and climate scientists. The phase state determines if and how fast such particles grow into cloud condensation nuclei on which water vapor can condense to form cloud droplets and precipitation.
Until recently, however, experimental observations of the solid-liquid phase transitions and humidity-dependent growth of atmospheric aerosol nanoparticles could not be explained by theoretical calculations and model predictions.
Scientists at the Max Planck Institute for Chemistry could now resolve the riddle. "The particle size is more important than we previously thought, "says Yafang Cheng, group leader at the institute in Mainz. "For example, salt particles can become liquid not only by increasing temperature or humidity, but also by reducing the particle size," says the lead author of a recent publication in Nature Communications.
The researchers around Yafang Cheng and Hang Su analyzed high precision measurement data on the hygroscopic growth of sodium chloride and ammonium sulfate nanoparticles exposed to varying relative humidity.
From these growth curves, the researchers calculated the interfacial energies and critical diameters for the solid-liquid phase transitions of the salt nanoparticles. According to similar analyses, the researchers expect that organic aerosol particles commonly occuring in large quantities in the atmosphere are always liquid at room temperature when their diameter is below approximately 20 nanometers.
"Based on our results the particle size should be considered as an additional dimension in the phase diagram of aerosol nanoparticles," says Cheng´s colleague Hang Su. “Our findings are also relevant for other research areas where nanoparticles play a role, including the biomedical and materials sciences.” For example, they may help to determine and control the solubility and concentration of therapeutic or reactive agents in in synthetic nanoparticles for medical or technical applications.
Cheng et al., Size dependence of phase transitions in aerosol nanoparticles, Nature Comm., 6, 2015, doi:10.1038/ncomms6923
Dr. Hang Su
Max Planck Institute for Chemistry
Dr. Susanne Benner | Max-Planck-Institut für Chemie
Complete skin regeneration system of fish unraveled
24.04.2018 | Tokyo Institute of Technology
Scientists generate an atlas of the human genome using stem cells
24.04.2018 | The Hebrew University of Jerusalem
At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.
Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...
Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.
Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
24.04.2018 | Life Sciences
24.04.2018 | Materials Sciences
24.04.2018 | Trade Fair News