A research team in Germany has developed a new type of polyamide that emits broad-spectrum white light under near-infrared laser irradiation — a property that could make the material promising for next-generation optical devices and LEDs.

Polyamides are synthetic polymers valued for their light weight, durability, and heat resistance. They are best known for their use in textiles, including high-performance fabrics such as nylon.

“Our objective was to investigate the possibility of redesigning these well-known polymers to facilitate novel interactions with laser light,” says Peter Schreiner, a professor at the Institute of Organic Chemistry at Justus Liebig University, who led the study.

A new spin on old materials

Polyamide materials have been around for decades. Nylon, introduced to the market in the late 1930s by the chemical company DuPont, became the world’s first commercial synthetic fiber and was later used in military uniforms and parachutes during World War II. In 1965, DuPont went on to develop Kevlar, an ultra-strong fiber that gives modern body armor its protective strength.

Aside from textiles, polyamides are also widely used in engineering plastics, automotive parts, electronics, and packaging. Their strength comes from intermolecular interactions known as hydrogen bonds, which link neighboring molecular chains in the material.

On their own, conventional polyamides do not generate light. That limitation inspired the team to rethink the polymer’s molecular architecture.

“Diamantane, a naturally occurring molecule found in crude oil, exhibits exceptional rigidity and thermal stability, resembling a miniature diamond,” Schreiner explains. He and his team replaced the conventional flexible building blocks of polyamides—one- and two-dimensional chains and ring structures—with these rigid three-dimensional diamantane units.

“In essence, replacing their flexible building blocks with rigid diamantane units transforms traditional structural polymers into materials with novel and advantageous light-emitting capabilities,” says Saravanan Gowrisankar, a co-author of the study and researcher in Schreiner’s group.

Under near-infrared laser irradiation, the diamantane-based polyamides emit broad-spectrum white light without the need for dyes, dopants, or inorganic salts — additives commonly used to tune white-light generation.

Such additives can diminish stability, complicate processing, and raise production costs.

“Our approach simplifies the material system, enhances stability, and is potentially more dependable and scalable for practical applications,” Schreiner says.

Aside from their light-generating capability, the diamantane-based polyamides have exceptionally high thermal stability: they remain intact well above 400 °C, whereas nylon-6 and nylon-66 fully decompose near this temperature.

This is important because light-emitting devices, particularly those driven by high-powered lasers, can generate substantial heat during operation, explains Gowrisankar. “If a material lacks the necessary heat resistance, it may degrade or lose its intended functionality,” he notes.  

This extra stability is also helpful during the fabrication process of any light-emitting device, which often involves harsh conditions.

“Numerous processing steps require elevated temperatures, and a heat-resistant material ensures that its structural and optical properties remain intact throughout the manufacturing process,” says Gowrisankar.

Surface structure key to white-light generation

The white light emitted by the diamantane-based polyamides depends in part on the material’s surface structure.

How the polymer chains are organized at the surface affects how the near-infrared laser energy moves through and interacts with the material; a rough or nanocrystalline surface enables efficient conversion of the laser energy into broad-spectrum white light, whereas a smooth surface does not.

“In the rubbery, smooth sample, the chains are highly flexible and lack a well-defined, ordered arrangement, so they are unable to interact efficiently with the incident laser field,” explains Schreiner.  

Currently, the researchers are exploring the use of lithography — a patterning technique used to create extremely small, precise structures on a surface — for the design of individual diamantane structures. They plan to create larger polyamide architectures that can be integrated into functional, high-performance thin films.

“To advance toward commercialization, we are addressing three key challenges: enhancing emission efficiency, integrating the material into device architectures, and developing scalable manufacturing,” says Schreiner.

Reference: Saravanan Gowrisankar, Marius Lang, and Peter R. Schreiner. The Nonlinear Optical Behavior of Linear Diamantane Polyamides. European Journal of Organic Chemistry (2025). DOI: 10.1002/ejoc.202500643

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