Hydrogen bonds for stable polymer structures

The stability of complex biological molecules such as proteins and DNA is largely based on hydrogen bonds. Inspired by these natural processes, researchers are investigating the application of these bonds in synthetic polymers. However, conventional materials often reach their limits in terms of mechanical strength and stability. A team from Tianjin University has published a comprehensive study on N-acryloyl glycinamide (NAGA)-based polymers. These materials use multiple hydrogen bonds to improve their mechanical and chemical properties and open up new application possibilities, especially for 3D printing.

The study, published in the Chinese Journal of Polymer Science, describes how NAGA-based supramolecular polymers can be adapted in terms of their structure and properties. The researchers categorize the polymers into three groups: those with exclusively cooperative hydrogen bonds, those with combined physical interactions and diol-based chain extenders. Each of these groups has specific mechanical and chemical properties that qualify them for different areas of application. Hydrogels based on PNAGA, for example, are said to have high mechanical strength and minimized swelling behaviour, which makes them ideal for tissue scaffolds and flexible electronics. Thermoreversible gels such as PNAGA-PCBAA enable a controlled transformation between liquid and solid state at body temperature and could be used for 3D-printed bioinks and injectable biomaterials.

Another field of research concerns ultra-solid PNASC hydrogels, which are characterized by their resistance to material fatigue. These properties can be further modified through targeted copolymerization or blending with other monomers. The researchers are also investigating NAGA diols as chain extenders for polyurethane networks in order to produce self-healing elastomers with high mechanical strength and easy processability.

“By precisely adjusting the chemical structures of NAGA-derived units, we can create materials with a wide range of properties,” said Professor Wen-Guang Liu, a leading expert in the field. “This level of versatility opens up a wealth of opportunities for developing advanced materials that can meet the diverse needs of various industries.”

In particular, these materials could enable significant advances in tissue engineering, wound healing and controlled drug release in the future.

Research suggests that 3D printing processes could benefit from the development of these materials. In particular, the ability to produce mechanically stable and biocompatible structures with variable morphology opens up new avenues for the additive manufacturing process. The next step is to further optimize the material properties and improve the scalability of production to enable industrial use.