Researchers at Waseda University in Japan have made a breakthrough in the development of optoelectronic materials, unveiling a new family of high refractive index polymers (HRIPs) called poly(thiourea)s (PTUs) that could revolutionize the industry. In theory, these polymers not only promise superior performance in transparency and light manipulation but also offer an eco-friendly alternative to the costly and environmentally damaging HRIPs currently in use.
The PTUs are characterized by their unique molecular structure, where each polymer chain includes a simple aromatic ring connected to a thiourea group. This design is crucial as it enables the formation of strong hydrogen bonds between the sulfur atoms of one thiourea group and the hydrogen atoms linked to nitrogen in another. These interactions lead to a densely packed, yet amorphous material, which maintains a high level of transparency—over 92%—along with an impressive refractive index of 1.81.
One of the most unique aspects of the PTUs is their sustainability. The research team, led by Professor Kenichi Oyaizu, has developed a straightforward and inexpensive method for recycling these polymers. The PTUs can be easily degraded into simpler molecules through mild heating and the addition of diamines, facilitating their reuse in new polymer synthesis.
Reference
Watanabe, S., Cavinato, L. M., Calvi, V., van Rijn, R., Costa, R. D., & Oyaizu, K. (n.d.). Polarizable H-Bond Concept in Aromatic Poly(thiourea)s: Unprecedented High Refractive Index, Transmittance, and Degradability at Force to Enhance Lighting Efficiency. Advanced Functional Materials, n/a(n/a), 2404433. https://doi.org/10.1002/adfm.202404433
