Stella Andréa Françoise Laperrousaz

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Thermally Drawn Elastomer Nanocomposites for Soft Mechanical Sensors

Chaoqun Dong, Stella Andréa Françoise Laperrousaz, Andreas Leber, Yunpeng Qu, Inès Richard, Fabien Sorin

Stretchable and conductive nanocomposites are emerging as important constituents of soft mechanical sensors for health monitoring, human-machine interactions, and soft robotics. However, tuning the materials' properties and sensor structures to the targeted mode and range of mechanical stimulation is limited by current fabrication approaches, particularly in scalable polymer melt techniques. Here, thermoplastic elastomer-based nanocomposites are engineered and novel rheological requirements are proposed for their compatibility with fiber processing technologies, yielding meters-long, soft, and highly versatile stretchable fiber devices. Based on microstructural changes in the nanofiller arrangement, the resistivity of the nanocomposite is tailored in its final device architecture across an entire order of magnitude as well as its sensitivity to strain via tuning thermal drawing processing parameters alone. Moreover, the prescribed electrical properties are coupled with suitable device designs and several fiber-based sensors are proposed aimed at specific types of deformations: i) a robotic fiber with an integrated bending mechanism where changes as small as 5 degrees are monitored by piezoresistive nanocomposite elements, ii) a pressure-sensing fiber based on a geometrically controlled resistive signal that responds with a sub-newton resolution to changes in pressing forces, and iii) a strain-sensing fiber that tracks changes in capacitance up to 100% elongation.

WILEY2023

Highly Integrated Multi-Material Fibers for Soft Robotics

Hritwick Banerjee, Nicola Bartolomei, Chaoqun Dong, Stella Andréa Françoise Laperrousaz, Andreas Leber, Bastien Schyrr, Fabien Sorin

Soft robots are envisioned as the next generation of safe biomedical devices in minimally invasive procedures. Yet, the difficulty of processing soft materials currently limits the size, aspect-ratio, manufacturing throughput, as well as, the design complexity and hence capabilities of soft robots. Multi-material thermal drawing is introduced as a material and processing platform to create soft robotic fibers imparted with multiple actuations and sensing modalities. Several thermoplastic and elastomeric material options for the fibers are presented, which all exhibit the rheological processing attributes for thermal drawing but varying mechanical properties, resulting in adaptable actuation performance. Moreover, numerous different fiber designs with intricate internal architectures, outer diameters of 700 mu m, aspect ratios of 10(3), and a fabrication at a scale of 10s of meters of length are demonstrated. A modular tendon-driven mechanism enables 3-dimensional (3D) motion, and embedded optical guides, electrical wires, and microfluidic channels give rise to multifunctionality. The fibers can perceive and autonomously adapt to their environments, as well as, probe electrical properties, and deliver fluids and mechanical tools to spatially distributed targets.

WILEY2022

Functionalized Fiber Reinforced Composites via Thermally Drawn Multifunctional Fiber Sensors

Baris Çaglar, William Nicolas Duncan Esposito, Stella Andréa Françoise Laperrousaz, Véronique Michaud, Dang Tùng Nguyen, Fabien Sorin

Monitoring fiber reinforced polymer composites (FRPC) during their production and operation is becoming crucial to track the performance of the final parts and optimize the overall life cycle. The challenges associated with integrating multifunctional sensors with the required aspect ratio, manufacturing scalability, robustness, and performance within FRPC parts remain, however, unresolved. Here, a novel class of electronic polymer fiber sensors that can be seamlessly integrated within FRPC, and can sense and decouple cure time, temperature, and strain during and postprocessing is reported. It is shown that the particular fiber geometry induces a minimal impact on the final FRPC microstructure. Integrating both capacitive‐ and resistive‐based sensors within the electronic fibers, the monitoring of the resin flow and its curing during the production of FRPC parts is demonstrated. Finally, the embedded fiber sensors are used to measure and decouple thermal and mechanical loads imposed on the parts during their use, paving the way toward a new platform for smart and connected fiber reinforced polymer composites.

2021