Programmable 3D Printing: Adjustable Stiffness in Thermoplastic Elastomers

In a study published in the journal Advanced Functional Materials, a team from Princeton University in the United States detailed their process of utilizing thermoplastic elastomers, a commonly used polymer, to craft 3D printed structures with adjustable stiffness. By manipulating the printing paths of the 3D printer, engineers can program the physical properties of the plastic, enabling it to stretch and bend in one direction while maintaining rigidity in another.

The researchers highlighted the potential applications of this technology in areas such as soft robotics, medical devices, prosthetics, lightweight helmets, and custom high-performance shoe soles.

The key to the material's performance lies in its smallest internal structures. The research team employed a block copolymer that forms rigid cylindrical structures of 5-7 nanometers in thickness within the elastomeric polymer matrix. Using 3D printing technology, the researchers positioned these nanoscale cylinders, rendering the 3D printed material stiff in one direction but soft and elastic in nearly all other directions. Designers can place these cylinders in different orientations within a single object, resulting in regions of the object exhibiting both stiffness and stretchiness.

Moving forward, the research team aims to delve into novel 3D printing architectures that will be compatible with applications such as wearable electronics and biomedical devices.