Prof. Jan Lagerwall, physicist at the University of Luxembourg, has obtained a Proof-of-concept grant from the European Research Council (ERC). He will work on the production of sheets and fibres of smart sensors applicable on various materials and therefore useable in monitoring the health and stability of buildings and in smart textiles, respectively.
The ERC Grant will support the project REVEAL “Revealing complex strain patterns and dangerous loads using cholesteric liquid crystal elastomers”.
Increasing need of mechanical sensors
The Internet of Things, Industry 4.0, and the increased availability and performance of sensors have led to new generations of smart products that can communicate real-time status information. Mechanical sensors, which are often measuring strain, are key components in many scenarios of smart objects.
“At large scale, they are invaluable for monitoring the structural health of our built environment, such as houses, bridges and event arenas. Distributed strain sensors are highly useful for detecting and monitoring cracks in concrete structures as a function of ageing and wear, and after extreme events like earthquakes, hurricanes, or flooding they can help determine if buildings have suffered dangerous plastic deformations. With the next generation of smart buildings being erected to counter these problems, there is a strong market opportunity for suitable mechanical sensors”, comments Prof. Jan Lagerwall.
However, current technology typically employs one-dimensional strain sensors with low spatial resolution (one sensor, one value), giving limited information about complex deformations. They may also miss dangerous strains that may be located slightly away from the sensor.
New solution
Prof. Jan Lagerwall and his team propose a solution offering two-dimensional distributed strain sensing with high resolution, as well as a one-dimensional version that is very interesting for smart textiles. Their two new concepts for non-electronic strain sensing, both based on the mechanochromic response of Cholesteric Liquid Crystal Elastomers (CLCEs), change colour in response to mechanical deformation. The value proposition of REVEAL comprises simple and scalable procedures for making CLCE sheets of large size and fibres of arbitrary length, which exhibit excellent an local mechanochromic response (from red to violet) upon strains of up to 200%.
“Through the Proof-of-concept, we will produce large-size CLCE sheets and long fibres, and assess their application potential, for instance in the monitoring of structures, smart clothing and sports gear. We aim notably to ensure that the CLCE sheets show consistent and tuneable colour with sufficient time stability. Finally, we will assess how useful and efficient the products are in specific target applications”, explains Prof. Lagerwall.
Images scientifiques de l’étirement d’une plaque CLCE © Université du Luxembourg
The sheets can be glued across their full area onto materials like concrete, wood, plastic, glass or steel surfaces. Application also spans into wearable items: fibres can be woven into fabrics or sewn into elastic garments without impairing user comfort, and they survive long-term use and machine washing. This new generation of smart textile fibres can be particularly useful in sports and healthcare clothing, wearable robotics, innovative fashion and art.
The research project will continue until 2024, after which a commercialisation phase will start. This is the third ERC grant obtained by Jan Lagerwall. He received an ERC Consolidator Grant in 2015 to carry out fundamental research into liquid crystals and their composite materials, followed by an ERC PoC grant based on the Consolidator Grant research.