Interface Science—What Happens at the Boundaries

The boundary where two different substances come into contact is called an interface. Taking a glass of water as an example, the surface of the water is the interface between the water (a liquid) and the air (a gas) above it. Interface science is the study of the phenomena that occur at such boundaries. Interfaces are all around us and are intrinsic to various phenomena, such as wetting, adhesion, surface tension, dispersion, adsorption and emulsification.

Surfactants change the properties of water and oil interface, making it mixed

A surfactant is a substance that acts on an interface to change its properties. Many products are essentially applications of these changes. For example, water and oil usually don’t mix, but there are many products in which they do, like skin care lotions and mayonnaise. This is possible because surfactants change the properties of the interface—the boundary—between water and oil. Surfactants are widely used in detergents, oral care products, pharmaceuticals, cosmetics and food products.

Why I was Fascinated World of Interface Science

Lead researcher Atsunori Morigaki explained his fascination with the field of interface science. “It was through my research on product flavors and fragrances that I began to see the depth of interface science and became interested. In my research, I wanted to gain a better understanding of why the perception of a fragrance changes when it is combined with other ingredients in a product, and how the different states of a fragrance affect the taste and smell of a product. To do this, I needed to know more about interface science, such as the state in which fragrances exist in a product. This led me to research interface science, and I realized that interface science is deeply involved with almost all of Lion’s products.”

 After coming to this realization, Morigaki requested to be reassigned from flavors and fragrances to interface science and began more in-depth study. First, he was assigned to laundry detergents. His research focused on the liquid laundry detergent applications of the widely used plant-based surfactant Methyl Ester Sulfonate (MES).MES is both high in detergency and environmentally friendly as a plant-based raw material. Because of these properties, it is widely used in powder detergents overseas, particularly in Southeast Asia. The overseas market for liquid laundry detergents has been growing, but MES is solid at room temperature and, in cooler climates like those of Northeast Asia that are cooler than Southeast Asia, it is known to separate out when used in liquid detergent formulas. To address this, Morigaki began studying ways to stabilize MES in liquid laundry detergents.

 Morigaki who laid the foundation for interface science through his research so far, that his research is being utilized in further research activities. “At first, I didn’t know enough about interface science, but I learned a great deal from looking at the research that Lion has done over the years as a detergent manufacturer. I also went to academic conferences related to interface science to keep up with the latest information and, in between other research assignments, worked on my own experiments to deeply explore the micelles formed by the surfactants within detergents. Thanks to this research, we were able to establish a technology to stabilize MES in liquid laundry detergent, although we ultimately decided not to use it in our products. However, I have been able to apply the interface science knowledge that I gained through this experience to many other research activities at Lion, which has really impressed on me how interface science technology is connected to all Lion Group products.”

Aiming to Visualize the Interfaces State from the Mission to Have Customers Use the Our Product with a Sense of Conviction.

Interface science is often thought of as applying only to laundry and dishwashing detergents, but it is actually used in a much wider range of products, including oral care and pharmaceutical products. In interface science research, it is important not only to control the interface but also to be able to visualize the interface state. In the latest project led by Ryota Hashimoto, research is underway to shed light on the specific effects of recently developed technology in the field of oral care.

 Fluoride is known to promote dental re-mineralization and prevent dental cavities and is used in many toothpastes. However, since most people rinse their mouths immediately after brushing, the fluoride gets washed away and its cavity-prevention effects are limited. To better prevent cavities, it’s important to keep the fluoride on the mouth for a longer time.

 Hashimoto explained, “We’re investigating innovative technologies to improve fluoride retention by increasing its chemical affinity with the tooth surface. With such new technologies, I believe it’s important to be able to clearly demonstrate their functions and communicate them to consumers as easy-to-understand evidence of the value of our products.”

 He continued “I think it’s important to evaluate these formulations under conditions that are as close to those of the real oral cavity as possible to make the value of our technology more convincing, so we used a model tooth surface for evaluation. The evaluation method involves quantitatively measuring the amount of fluoride ions on the model tooth surface and analyzing their distribution with a special microscope. Currently, new technologies now achieve uniform, concentrated fluoride retention on the tooth surface, suggesting that they may be effective in preventing cavities.

 Morigaki added, “Because Lion develops a wide variety of products, we are able to make the most of really full range of knowledge in a number of fields to formulate, evaluate and test hypotheses. I think it’s definitely an advantage to have access to this knowledge, which allows us to view each challenge from a broader perspective.”

Pursuing the Possibilities of Interface Science Possibilities as a Team of Professionals

Academic research in interface science often requires pioneering areas that are both conceptually and technically unexplored. On the other hand, the main role of a manufacturer’s research is to pay close attention to such academic research, apply the findings to products used in real life, and make the functions of the products apparent so that consumers will want to use them.

 Hashimoto explained, “In some cases, even if there is a difference at the microscopic nanoscale, it doesn’t change the functionality of the product at all. We are constantly using visualization technologies for checking products’ actual effects to see if the changes we have made to product formulas really affect the product’s functionality and will be useful for consumers.”

Morigaki added, “It’s important to keep up with academic developments in cutting-edge technology via academic conferences and published papers. As a researcher for a manufacturer that serves consumers through its product development, rather than just adopting new technologies as-is, I am always conscious of the need to fit them based on our perspectives and approaches in order to create products that will satisfy consumers.”

Lion’s interface science research is divided into product areas. Each team member is in charge of a specific core technology and develops expertise as an autonomous professional in that area. The knowledge they gain individually through this approach is then accumulated and reapplied to other fields, leading to the development of products that are unique to Lion.

Morigaki continued explaining, “Team meetings are an extremely important place for us to exchange information. Based on the shared understanding that meetings are not for scheduling but instead a forum to share ideas, each member participates as an autonomous professional, with both new and more seasoned employees alike engaging in lively discussions. I have personally learned a lot from the discussions and am quite inspired by them. My role as a leader is to build bridges both between our own researchers and between Lion and universities and other companies in order to create new possibilities for interface science.”

Pushing Ever Forward in Our Research with Pride and Professionalism

Lion has been working in the field of interface science for more than 100 years, and we are committed to the visualization of interface conditions based on the desire of each and every researcher to deliver products that can be used with confidence by consumers.

Yukari Sekine explained, “I’m mainly responsible for addressing technology development in the hygiene field. Recently, we indicated that ingredients in toothpaste causes virus inactivation, which means a loss of viral titer with time. Therefore, I would like to visualize how they act on the viral surface and understand the mechanism behind the effect essentially. I find it very rewarding when I discover the essence of the solution to a consumer’s problem.”

 Nodding in agreement, Shinya Sudo adds his thoughts on the team’s future, saying, “We, the interface science team, seek to raise consumers’ expectations for and satisfaction with our products by elucidating product functions. We will strive to continue creating technologies that lead to unique and highly effective products by making full use of the knowledge and experience in interface science cultivated across Lion’s wide range of products. To be a reliable team of interface science professionals, we will continue to push forward with our research as we continue to challenge ourselves and improve our technologies.”

Lion strives to create products that make a difference in everyday lives, and interface science is the source of the technology that allows us to do so. Lion will continue to advance research, steadily and surely, in the field of interface science.

Affiliations are as of the time of the interview. (Interviewed May 2022)