Three-dimensional printing of hierarchical liquid-crystal-polymer structures

Area of Science:

• Materials Science
• Polymer Chemistry
• Additive Manufacturing

Background:

• Fibre-reinforced polymers offer high stiffness and strength for demanding applications like aerospace and biomedical implants.
• Current limitations include energy-intensive fabrication, brittle fracture, and difficulties in shaping and recycling.
• Biological materials achieve remarkable properties through hierarchical self-assembly and circular integration.

Purpose of the Study:

• To develop a 3D printing approach for creating recyclable, lightweight structures with hierarchical architectures and complex geometries.
• To achieve unprecedented stiffness and toughness in 3D-printed polymers by controlling molecular orientation.
• To bridge the gap between top-down manufacturing freedom and bottom-up molecular control.

Main Methods:

• Utilizing a three-dimensional (3D) printing technique with liquid-crystal polymer (LCP) feedstock.
• Controlling the self-assembly of LCP molecules into highly oriented domains during melt extrusion.
• Aligning molecular domains along the print path to reinforce the polymer structure based on mechanical stress requirements.

Main Results:

• Demonstrated the creation of recyclable lightweight structures with hierarchical architectures and complex geometries.
• Achieved stiffness, strength, and toughness that surpass current 3D-printed polymers by an order of magnitude.
• Properties achieved are comparable to high-performance lightweight composites.

Conclusions:

• The developed 3D printing method enables the fabrication of advanced polymer structures with superior mechanical properties.
• Self-assembly of liquid-crystal polymers offers a pathway to design and realize complex, high-performance materials.
• This approach overcomes limitations of traditional manufacturing, allowing for greater design freedom and material recyclability.