Interview with Dr. Alexandra Latnikova

MICROENCAPSULATION

1

My name is Alexandra Latnikova and I work at the Fraunhofer Institute for Applied Polymer Research in the Microencapsulation and Particle Applications Group. I became interested in microencapsulation about 10 years ago when I moved from Russia to Germany and started my PhD thesis devoted to the development of smart anticorrosion coatings containing micro- and nanocapsules.

As soon as the PhD thesis was finished I started to look for ways to apply the knowledge I had acquired and make it more broadly useful. Fraunhofer struck me as a very interesting organization to work with, since it is the place where the world of ideas (science and creativity) overlaps with the material world (business, implementation and product development) on an everyday basis, which I found and still find very stimulating and inspiring. I believe that perceiving both worlds simultaneously helps me to gain an integral knowledge about how the universe functions and to understand what my own place in it can be.

1) Can you tell us more about the Fraunhofer Institute for Applied Polymer Research? What are the goals of the organization?

Fraunhofer is the largest application-oriented research organization in Europe. Our Institute’s website states that: “Fraunhofer Institute for Applied Polymer Research (IAP) specializes in researching and developing polymer applications. It supports companies and partners in the customized development and optimization of innovative and sustainable materials, processing aids and processes. In addition to characterizing polymers, the institute also produces and processes polymers in an environmentally-friendly and cost-effective way on a laboratory and pilot plant scale.” I personally would formulate the main goal of the organization as bringing up-to-date polymer science to serve the current needs of society. These needs are identified through communication and collaboration with local and international companies active in relevant brunches of industry, as well as through ongoing dialogue with  local government and through monitoring  emerging trends around the globe.

Based on these inputs we decide at which level our engagement is the most reasonable. For example, companies often contact us because they have a problem that they cannot solve alone due to a lack of time, knowledge, or equipment. In this case, our role is to find a customized solution as quickly and effectively as possible (on a several months scale) using the portfolio of the whole institute (a network of approximately 200 scientists with a very broad range of backgrounds). In some cases short-term solutions are not possible, and in this case we prefer to engage in longer-term publicly-funded research projects (several years scale) and develop strategies and solutions together with our partners. Combining both strategies gives us an opportunity to be aware of the current needs, as well as to keep our know-how up-to-date.

The institute is divided into divisions, which consider various aspects and application fields of polymer chemistry, polymer physics and polymer biology. More information about the structure of the institute can be found here: https://www.iap.fraunhofer.de/en/about_us/Overview.html

2) Your recent research projects are in the field of microencapsulation and particle applications. Can you tell what this is it about (e.g. goals, scope, duration of the projects, expected outcome…) and how it can be applied in different fields?

“Microencapsulation and particle applications” is the name of our working group, which belongs to the division of Synthesis and Polymer Technology. This group started its first microencapsulation activities about 30 years ago. Since then the group members have been screening, evaluating, selecting, developing, refining and tailoring the whole available spectrum of microencapsulation technologies and approaches presented in the academic and patent literature in order to be able to offer the technologies with the best possible output.

Microencapsulation is the generic term for numerous technologies, which are often utilized when the release rate of a certain functional substance in a medium has to be controlled and/or contact between the active substance and the medium has to be prevented (for example if the substance reacts with other components or with the environment). This is achieved by wrapping the tiny particles or droplets of the functional substance (capsule core) with a thin layer of another material (capsule shell). The permeability of the shell determines whether, how fast and under which conditions the active material will be released.

Most of the processes used for the production of microcapsules are self-assembly processes, which means that we are able to produce very complex micro-structured materials in a few synthesis steps using broadly available equipment with very high precision and in large  quantities. To produce our capsules we use commercially available synthetic and natural polymers and building blocks in order to shorten the path to commercialization. The processes used for the microencapsulation are very diverse and include emulsion-based, as well as spraying and dripping technologies.

We intentionally do not prioritize any application direction, since we believe that an interdisciplinary approach is best at this point. It allows us to keep a good overview of available technologies, combining them and getting inspiration for the development of new ones. For example, we produced microcapsules containing:

– Perfumes for personal care applications, which release smell over months and/or repel insects

– Catalysts, which can be released at a chosen temperature to activate a glue or sealant

– Plastic additives, which can be more homogeneously distributed in the polymer matrix

– Probiotic bacteria, which should survive  passage through the stomach

– Phase change materials, which store thermal energy and release it over night

– Photochromic pigments, which migrate in a polymer matrix and deactivate if not encapsulated

– Microelements, which must be released in a specific part of the digestive system

3) Do you have other research projects in the field of microencapsulation ongoing or recently finished? What were they about? Which projects were successfully implemented on the market?

Currently, one of our projects is devoted to the microencapsulation of a biocide. The goal of the project is to encapsulate the biocide in such way that it would be released from an architectural coating 5 times slower than if it were not encapsulated. This allows us to either prolong the lifetime of the coating substantially (for example, a five year guarantee instead of two years), or to reduce the amount of the biocide in the coating (sometimes several times) without changing the antifouling performance. This is possible because the amount of biocide actually added to the paint is much higher than necessary for the protection from microorganisms. The problem is that the biocide molecules are very mobile and leak out of the coating after two years. When released into the environment at high concentrations, biocides can harm other organisms, which were not initially targeted. Thus, microencapsulation allows us to improve the quality of the product, while simultaneously saving money and protecting the environment. The same principle is applied for ship antifouling coatings, as well as for pesticides and fertilizers used in agriculture.

4) In which field(s) do you foresee microencapsulation having the biggest impact and why?

We think that, in the short term, microencapsulation will mainly impact those application fields that rely on utilization of functional substances in low concentrations or where the concentration of the functional substance must be carefully controlled. These include all the application fields for biocides, pesticides, fertilizers and, of course, medical applications (drug delivery). We believe that these applications also have the highest social impact and can be implemented on the market more successfully than some others, because they simply have higher priority at the moment.

Over the long term, we expect microencapsulation to eventually penetrate every field of life, since it allows for fabrication of materials with very defined and complex microstructures. Microstructuring, in turn, opens the door to so called smart, responsive and programmable materials, which are able to sense and react to the environment autonomously.

 

5) What are the main challenges encountered when conducting microencapsulation experiments?

One of the main scientific challenges is tailoring  microencapsulation processes to athe particular functional substance. When we initially develop a technology in the lab, we test it with several model substances to see if it can be used for substances with various properties. Often, when we change the model substance, we have to change the whole recipe, since self-assembly processes are very sensitive to  minor changes in the environment. We need to have a very deep understanding of the processes on the molecular level, as well as trust our scientific intuition, in order to succeed in this task.

Another challenge is when we want to keep the process going the same way and keep the final quality of the product, but to change the building blocks. For example, at the moment many companies are interested in making their microcapsules biodegradable without changing their performance. This is a very interesting challenge, which will have a huge social impact and hopefully help to protect our environment from plastic accumulation. Therefore, we accept this challenge gladly and are trying our best to solve it.

Another common challenge is to find a holistic solution, which combines the most reasonable process, the best-performing encapsulating material, and the lowest possible price simultaneously. It is not always possible to solve this puzzle, but whenever we succeed, the  path to commercializing the product becomes considerably shorter.

 

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