Professor Essi Sarlin is on a mission to develop sustainable plastics

Following an uninterrupted 18-year career on the Hervanta campus, Essi Sarlin was promoted to a professorship in materials science in the Faculty of Engineering and Natural Sciences in July 2024. Sarlin began investigating the properties of materials early in her studies towards a master’s degree. While working on her doctoral dissertation, she narrowed her focus to polymeric materials.

Sarlin finds that a professorship adds weight and credibility to grant proposals, aiding in the development of her research group. 

She says the best part of her current role is working with young people. She spends more than 50% of her working hours supervising and collaborating with researchers and roughly 25% teaching and instructing students. 

“I thoroughly enjoy conducting research with doctoral students and postdocs. Being surrounded by smart young people is so invigorating!” 

Being born with an inquisitive mind is perhaps the main reason why Sarlin naturally gravitated towards a research career. 

“I am easily excitable, endlessly curious and always looking to broaden my knowledge. In research, there are always more questions than answers. Every answer breeds five new questions, and my thirst for knowledge is insatiable,” she says.

One of the most pressing unanswered questions in Sarlin’s field concerns plastics.

How can we address the unsustainability of plastics?

Essi Sarlin and her colleagues in the Plastics and Elastomer Technology research group study a variety of polymer-based materials, including plastics, rubbers and their composites. The group’s primary goal is to develop an in-depth understanding of these materials to support their development and promote the sustainable development of polymer products in general. 

According to Sarlin, plastics are better than their reputation.

“Polymers are incredibly important materials but relatively inexpensive and often underappreciated, which has led to an array of challenges that we still do not fully understand. For instance, the effects of microplastics accumulating in the environment, animals and humans remain partly unclear. However, the challenges associated with plastics are not inherently due to the materials themselves but are largely related to consumption patterns and waste management. Considering sustainability is especially important in my line of work,” she says. 

For example, in the EU-funded project Recycling Technologies for Circular Reuse and Remanufacturing of Fibre-reinforced Composite Materials (RECREATE), Sarlin’s research group is investigating optimal methods to valorise recycled fibre-reinforced composites to ensure that new composite structures are both safe and durable. They are meticulously measuring the mechanical properties of these materials and their interfaces on a microscopic level, and then combining these results with findings from other experiments. They aim to predict how the microscopic mechanical properties of fibre-reinforced composites change during recycling and how the changes affect the durability and functionality of composites on a larger scale. 

In addition, Sarlin’s research group has devised a method for analysing how the properties of plastics change during sewage sludge processing. The results shed light on the impact of wastewater treatment processes on the concentration of microplastics found in sewage sludge. While sewage sludge is both nutritious and useful, the potential risks posed by the accumulation of microplastics require further investigation. This research is carried out in collaboration with environmental engineering specialists. 

Photo: Jonne Renvall, Tampere University

Strong tradition of collaboration in the fields of engineering 

The fields of engineering have a long-standing tradition of researchers working together and engaging in collaborative research and development activities. According to Essi Sarlin, this tradition is evident not only in active collaborations with companies but also in the frequent co-authorship of research papers by a large number of researchers. A multidisciplinary approach is highly valued in engineering: research problems are collaboratively explored from multiple perspectives, with each participant contributing their expertise to reach a shared conclusion. Collaborative activities take place both within academia and with industry partners.

“The impact of company collaboration is unequivocally positive and highlights the importance of our work. I find that engineering, in particular, is a field where the positive impacts of research on society, which is what ultimately matters in the grand scheme of things, are often realised through collaborations with companies,” Sarlin points out. 

Sarlin places great importance on being able to advance sustainability in the plastics industry through her research.

“Our research findings demonstrate to companies that the solutions we have developed address and resolve real-life issues, while also encouraging them to put new ideas into practice through R&D.”

Salsa dancing lifts the burden of decision-making 

Although Sarlin attained a professorship – the pinnacle of an academic career – at a young age, she maintains she is not particularly career-oriented. She is more interested in the actual work than everything around it. 

“The opportunity to do what I am excited about is enough for me. Is still have 30 years left in my career, so I am definitely not looking to set my future plans in stone,” she says, laughing.

A professorship is a demanding leadership role that involves continuously making decisions that have an impact on numerous issues and individuals. Sarlin finds that exercise, music and social interaction provide the perfect counterbalance to her work. In salsa, all these three elements come together seamlessly.

“Salsa is extremely relaxing, joyous and uplifting. Dance classes demand a level of concentration that is essential for maintaining my brain health. When dancing with a partner, I take on the role of a follower, making absolutely no decisions. I focus entirely on bodily communication and interpreting my dance partner’s cues, all the while fully enjoying the music and the exercise. Salsa requires wholehearted focus,” Essi Sarlin says, her eyes twinkling.