Sustainable, self-repairing, antimicrobial polymers developed

From medicine to electronics and optics, new materials developed by scientists at Kaunas University of Technology (KTU) can be applied in various fields where cleanliness, precision and durability are essential. As described in the journal Biomacromolecules, these materials are notable not only for their functionality but also for their sustainability: they are made from renewable raw materials, and no solvents are used during production.

The materials belong to a class called vitrimers, a relatively new type of polymer discovered only about three decades ago and named just 15 years ago. As explained by KTU Professor Jolita Ostrauskaitė, “Vitrimers are thermosetting polymers that, thanks to dynamic covalent bonds, can be thermally reprocessed or reshaped, similar to thermoplastics. At certain temperatures, they can self-heal after damage and also retain a temporary shape that can later be restored — this is known as thermally responsive shape memory.”

Until now, most vitrimers were derived from petroleum resources and required catalysts for processing. But according to Ostrauskaitė, “The polymers we have developed are unique because they are made from plant-based compounds, cured under UV or visible light, and do not require catalysts for processing. This happens naturally due to the chemical structure of the material itself.”

This is important not only because it simplifies the technological process but also for sustainability — catalysts are often expensive, derived from non-renewable resources, or even toxic. By eliminating them, material consumption is reduced, no additional additives are needed, and the technology becomes simpler, safer and more environmentally friendly.

Ostrauskaitė said the team’s most significant achievement was combining, in a single material, plant-based origin, radiation-induced polymerisation, self-repairing ability, shape memory, antimicrobial effect, and suitability for optical 3D printing. “Such multifunctional and sustainable solutions are still very rare, making this an important step forward both scientifically and industrially,” she said.

According to the researchers, optical 3D printing with the material can be performed at room temperature, consumes less energy and generates less waste. When exposed to UV or visible light, these polymers can be printed in complex shapes, such as medical device connectors.

“We successfully printed a Y-shaped connector — a typical medical component used to join tubes in infusion or respiratory equipment,” Ostrauskaitė said. “This part requires high precision, making it an excellent test of the material we developed.”

Optical 3D printing technology also allows the production of other complex components, such as optical lenses or electronics parts, which demand extremely precise dimensions and geometry. Additionally, the material can be shaped into temporary structures that can later be transformed or repaired — invaluable for prototyping and quickly responding to industrial needs.

Another important innovation is the polymers’ antimicrobial properties, arising from structural fragments in their composition. Test results showed that the materials effectively inhibited standard and other common microorganisms.

“The starting compounds used in the study were obtained from plant oils and by-products of biodiesel production, and certain fragments interfere with bacteria and other microorganisms, disrupting their vital functions,” Ostrauskaitė said. “This is why such materials can be used to create surfaces or products that must remain clean and hygienic, for example in medical devices, electronics, sensors or other items where microbial control is critical.”

Image caption: Y-shaped connector successfully printed by KTU scientists.