MIE Assistant Professor Sushant Anand and his researchers have made several breakthroughs in oil-water mixtures or "emulsions". Now, researchers have taken their research to a new level by self-assembling nanoparticles around droplets to form ultra-small (100-400 nm) nanoemulsions.

Traditional methods of making nanoemulsions have multiple steps, but Anand and his team have developed a single-step technique to create faster, more energy-efficient and smaller nanoemulsions. The results of this study were recently published in the ACS Applied Materials and Interfaces journal entitled " Synthesizing Pickering Nanoemulsions by Steam Condensation" .

“Nanotechnology plays a huge role in dealing with many of the problems of today's era. Taking oil-water emulsions as an example. The use of droplet size 'nano' can make a huge difference in the shelf life of many emulsion -based products (such as cosmetics) . Conveying and many billion-dollar industries. Surfactant molecules are often used to prevent droplets from getting together. But such molecules can have adverse effects in many cases. Therefore, there is growing interest in making surfactant-free Nanoparticle-stabilized emulsion," Anand said.

The challenge for the team was to make a nano-droplet emulsion of nanoparticles called Pickering Emulsion. “The manufacture of this lotion with nanoscale droplets has been a very big challenge for decades,” Anand observed.

In an article previously published in Nature Communications , Anand and his partner at the Massachusetts Institute of Technology said they could create nanoemulsions in which droplets are stabilized by surfactants. Anand and his students wondered if this new technology could be used to make Pickering nanoemulsions, so they continued to discover this.

“Emulsifiers can be made in many different ways, but unfortunately, for surfactants, they don't necessarily work for nanoparticles . So we can't guarantee that we will succeed,” added Dong Jinkang, a postdoctoral fellow working under Anand's guidance. “But the new technology has indeed achieved its goals.”

The process involves taking the oil and cooling it below the dew point to allow the water to condense on the oil. If the oil has suitable properties, and if it has a sufficient concentration of nanoparticles, the water droplets will self-disperse in the oil and nanoparticles. Self-assembly will be built around them to make nanoemulsions.

“What we showed at work was that we made a minimal nanoparticle nanoparticle-containing emulsion. What's exciting is that these emulsions are manufactured in the traditional way, they have to go through multiple steps. And they need to be very good. High particle concentrations can be made into small nanoemulsions. But we can make emulsions in minutes and make them very small - 10 times lower than what people tried to do before," Anand said, he is UIC's Anand Research Group Lab. . “Our technology is highly scalable and can be used at an industrial level. We have proven that it is highly energy efficient compared to current technologies for preparing emulsions.

"This technology opens up new gateways and opportunities - from membranes to drug delivery applications," said Hassan Bararnia, a PhD student at Anand.

“We can apply these emulsions to other areas, and it can have an impact on many industries – the possibilities are huge. Currently we use simple silica nanoparticles, but we can use different types of nanoparticles, such as organic/inorganic Core-shell nanoparticles, "Kang added.

Anand agreed, but there is such a saying, "The possibilities exist, but the challenge is also true. This is where all the excitement is - overcome them!"

In a recent work in the nanoscale journal , Kang and Anand developed a new method for making simple and complex nanoparticles called nanoparticle synthesis through bubbling vapor precursors in bubbling liquids. .

“The key advantage of our technology is that we can create complex particles with uniform properties without any side reactions and can fine-tune the shell thickness around the nanoparticles,” Anand said.

The work of Anand and his team has drawn the attention of peers around the world.

“Dr. Anand and his colleagues are very novel and timely on the colloidal particle-stabilized nanoemulsions,” said Dr. Bernard Binks, a world-renowned expert in physical chemistry at the University of Hull in the UK. About the theme of Pickering Lotion. “The pulverization method of breaking droplets into submicron has proven to be very challenging. This work starts with molecular water vapor and grows droplets to a specified size, partly determined by particle concentration. Colloid scientists and industrial research People will be very interested in this. Also."

Further exploration: a condensing-based method can produce a stable nano-sized emulsion

More information: Dong Jinkang et al. Synthesis of Pickering Nanoemulsion by Steam Condensation, ACS Applied Materials & Interfaces (2018). DOI: 10.1021 / acsami.8b06467