Material science: Changing the future of 3D printed polymer networks

This development, led by a team from the University of Colorado Boulder and detailed in the journal Science, introduces an innovative method for producing highly entangled polymer networks. These networks consist of tightly interwoven molecular chains that enhance the mechanical properties of polymer-based materials, offering a promising new avenue for producing durable and flexible materials.

The technology behind the innovation

At the core of this breakthrough is the concept of incorporating dense polymer chain entanglements within a single network. These entanglements significantly improve the material's stiffness and toughness.

Traditional manufacturing techniques, such as digital light processing (DLP) in vat photopolymerisation, have struggled to achieve such dense entanglements. This new method, however, overcomes these limitations, enabling the creation of materials that are both highly durable and flexible.

What does it do?

This technology transforms the production of hydrogels and elastomers, resulting in materials with extension energies four to seven times higher than those produced by conventional methods. These enhanced mechanical properties make the materials suitable for applications requiring high durability and flexibility, such as medical devices, wearable technology, and soft robotics.

How does it work?

The process combines light and dark polymerisation, where light initiates the formation of polymer chains, and darkness allows these chains to continue reacting and entangling without additional light exposure. This dual approach ensures that polymer chains are densely packed and entangled, resulting in materials with superior mechanical properties.

This method also achieves high monomer conversion at room temperature without the need for additional stimuli like light or heat post-printing. As a result, researchers can manufacture high-resolution, multi-material structures with features such as spatially programmed adhesion to wet tissues.

Discovery process

The research team aimed to transcend the limitations of traditional vat photopolymerisation techniques. By combining light and dark polymerisation processes, they developed a method that facilitates the dense entanglement of polymer chains, significantly enhancing the mechanical properties of the materials.

Extensive experiments confirmed high monomer conversion at room temperature, achieving the desired mechanical properties without needing additional stimuli post-printing. These findings show that this method can produce materials with significantly higher extension energies than those created using traditional DLP methods.

Applications

This technology has a broad range of applications across various fields requiring materials with high durability and flexibility:

• Medical devices: The ability to produce materials with spatially programmed adhesion to wet tissues is ideal for creating advanced medical devices and implants, such as internal bandages that deliver drugs directly to the heart or cartilage patches that repair joint damage.
• Wearable technology: Enhanced mechanical properties improve the durability and flexibility of wearable devices, making them more resilient to daily wear and tear.
• Soft robotics: The capacity to produce highly flexible and tough materials is beneficial for developing soft robotics, which require materials that can withstand significant deformation while maintaining structural integrity.

Future applications

As research progresses, it is anticipated there will be advancements in various areas of industry:

• Biomedical engineering: The development of advanced prosthetics and tissue engineering scaffolds is a promising application. These materials can create implants that mimic the mechanical properties of natural tissues, improving patient outcomes.
• Aerospace: The creation of lightweight, durable materials for aerospace components is another potential application. These materials can withstand the harsh conditions of space travel while maintaining structural integrity.
• Consumer electronics: The improvement in the durability and flexibility of electronic devices can enhance their performance and lifespan. For instance, flexible screens and durable casings can make devices more resistant to damage.