Additive manufacturing of functional structures and metamaterials

The ERC Advanced Grant project IMMENSE focuses on the development of smart and adaptive structures and materials that can autonomously respond to environmental stimuli. Central to this initiative is the use of additive manufacturing to create functional materials that can process information, potentially replacing digital signal processing.

A key advancement in this project is the development of a conductive photopolymer resin incorporating multi-walled carbon nanotubes (MWCNTs). This innovation allows for the creation of complex 2.5D and 3D structures using stereolithography (SLA), integrating conductive and passive resins to form components with built-in circuitry, eliminating the need for additional conductive elements.

One notable feature of this new material is its temperature-dependent conductivity, which has been utilized to create a flexible temperature sensor. By adjusting the concentration of MWCNTs, the material's response to temperature can be fine-tuned, enabling the design of devices with varied reactions to thermal changes.

The IMMENSE project also explores metamaterials, which have engineered structures that exhibit unique properties. These materials can generate bandgaps to block specific frequencies, useful for noise reduction and vibration control. Graded metamaterials, inspired by the cochlea's frequency-selective behavior, allow for spatial localization of vibrations, facilitating frequency identification without digital processing.

Incorporating liquid resonators, the project has developed metamaterials that trap low-frequency waves, with the ability to adjust bandgaps by altering the liquid content. This design enhances versatility for various applications. A proof of concept demonstrated the use of liquid sloshing to achieve rainbow sensing at low frequencies, with piezoelectric cantilevers converting mechanical vibrations into electrical signals.

The IMMENSE project illustrates the potential of additive manufacturing in creating multifunctional materials and adaptive metamaterials. The integration of MWCNT-based resins and graded metamaterials highlights the possibilities of combining material formulations with innovative designs to achieve advanced functionalities in sensing and vibration control.