Natural nEUROactive Mechanical mETAmaterials

Project Information

NEUROMETA

Grant agreement ID: 101020715

DOI

10.3030/101020715

EC signature date 13 June 2021

Start date 1 October 2021

End date 30 September 2026

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 2 478 140,00

EU contribution

€ 2 478 140,00

Coordinated by

UNIVERSITY OF BRISTOL
United Kingdom

Periodic Reporting for period 2 - NEUROMETA (Natural nEUROactive Mechanical mETAmaterials)

Reporting period: 2023-04-01 to 2024-09-30

Summary of the context and overall objectives of the project

Problem:
Metamaterials with anomalous and counter-intuitive multiphysics behaviours have been developed during the last two decades to help communication systems, sensing and robotics. Paradigmatic developments in artificial intelligence, Digital Twin approaches and additive manufacturing are pushing the design and production of metamaterials also towards the development artificial equivalent of synapsis and programmability. These advanced metamaterial concepts are however fossil-based and tend to make use of materials with a high carbon footprint and heavy life cycle costs in terms of emissions and environmental sustainability. Sensing/actuation mechanisms are also innate in natural plant fibres, spider silk strands and enzymatic systems, and involve saturation, hygromorphism, piezoelectricity and controlled hysteresis that could provide similar synaptic behaviours. Programmable memory properties could also be mechanically created in solid matter, and similar mnemonic-type architectures abound in natural fibres and related composites. While neurogenesis in electromagnetic metamaterials is at early stages of development, no neuroactive mechanical metamaterial concept and design based on biobased materials has been developed so far.

Important for society:
Develop metamaterials with biobased sources
Develop metamaterials with surrogate memory matter with sustainable capabilities

Objectives:
The project aims at developing this paradigmatic new class of metamaterials. We will explore the use of natural fibre composites, bio-based matrices, spider silk strands, 3D printing of bioblock materials and natural piezoelectricity in wood/cellulose combined with metamaterial architectures to develop artificial bio-based and sustainable surrogates of programmable memory with learning/adaptive behaviours similar to artificial neural networks. These metamaterials will autonomously learn from their past loading history and generate resilience in the structures in which they are embedded. The natural materials will also have low carbon footprint and could be further developed by worldwide R&D communities based on the resources locally available

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

During this period, the following actions have been implemented:

. Developed a numerical framework to predict the mechanical properties needed to simulate memory matter characteristics in bio-based materials (hydrogels, systems of natural fibers, composites with hygromorphism).
. Developed classes of bio-based composites, metamaterials, and hydrogel systems, which are used as platforms for mechanical memristor/synaptic properties to induce memory matter.
. Supported the NEUROMETA core projects and used the NEUROMETA infrastructure to promote research activities across existing postgraduate and undergraduate projects relevant to the ERC action.
. Published 25 papers in international journals, acknowledging the support of NEUROMETA.
. Prospective/Critical Review papers on 4D printing of hygromorph structures, ionic liquid-based biobased materials and development of high-value biobased materials from animal waste.
. Filed a UK patent (Metabiogel Absorber) based on initial results about the energy absorption and vibration damping properties of one of the bio-based materials used in NEUROMETA.
. Presented findings from the NEUROMETA project at 5 conferences (SPIE 2022, DRaF 2022, MIMS 2022, ICCM23, EuroEAP 2023).
. Promoted the NEUROMETA project at invited workshops in the UK, at the UK Metamaterials Network Conferences (2022 and 2023), and at invited keynotes/pitches (Italy, France, Brazil). The audiences were scientific, industrialists, and policymakers.
. Gave a seminar to the general public about metamaterials and NEUROMETA concepts, with a live TV interview on RAI 3 news.
. Set up activities with the collaboration partners listed in NEUROMETA, including visits and student exchanges with Professor Tulio Halak Panzera from USFJ and Professor Abderrezak Bezazi from U Guelma.
. Hired three new postdoctoral researchers and one PhD student. The NEUROMETA researchers are trained to be highly interdisciplinary, with skills covering metamaterial mechanics, dynamics and actuation, and biobased materials engineering.
. Purchased the necessary equipment for the project, including a Dynamic Mechanical Analyzer.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Progress beyond the state of the art:

. Programmable and multifunctional shape memory epoxy/flax fiber hygromorph composites, to be used as platforms for stimuli-responsive and shape-programmable metamaterials and metasurfaces.
. 4D printed PLA/flax metamaterials with programmable temperature/humidity responsive characteristics.
. Bio-based hydrogels based on alginate/poloxamer and different classes of natural fibre reinforcements (flax, cactus) with enhanced mechanical, humidity-responsive, and vibration-damping properties.
. A new series of mechanical metamaterial concepts based on bio-inspired designs (beetle elytra) and auxetic porous materials, to be used as platforms for future mechanical neuroactive metamaterials.
. A new series of bio-based coatings to enhance the multifunctionality and strain-rate dependence of porous and textile substrates, for hosting memory matter/memristor hydrogel materials.


Expected results until the end of the project:

. Development of hydrogel-based memristor as the synaptic unit for mechanical metamaterials neural networks
. Development of biobased textile/mechanical metamaterials substrates to host the synaptic units to generate the neuroactive metamaterials platforms
. Development of the distributed actuation system with biobased components (wood for piezoelectricity, biobased conductive coatings for temperature-based actuation) in the neuroactive mechanical metamaterials
. Development of a mechanical test rig to verify the memory matter characteristics of the metamaterial platform.

General NEUROMETA graphical abstract

How memristor-based hydrogels could be used to produce neuromorphic/neuroactive charateristics

Alginate/Poloxamer/Flax hydrogel - mechanics and 4D printing morphing

Biobased hygromorph metasurfaces with multiple programmable shape functions