Bottom-up assembly of Functionalized Nanohelices: a further step towards flexible devices – NANOHELIFLEX
Bottom-up assembly of functionalized nano-helices: a further step towards flexible devices
New strain sensors with linearity and reliability beyond current data
Flexible and biocompatible strain sensors based on nanoparticle (NPs) assemblies show great potential for various future applications, such as electronic skin, flexible touch screens, and robotics. The high sensitivity of such strain sensing devices is due to the exponential dependence of the tunnel resistance on the distance between adjacent NPs, which is altered by the strain. However, the sensitivity, reproducibility, and stability of these sensors are affected by variations in thickness, morphology, and density of the films during manufacture or during their application. The objective of this work was to develop strain sensors based on assemblies of silica nanohelices covered with conductive metallic NPs or semiconducting metal oxide NPs to overcome these critical aspects.
Gold NPs were synthesized and functionalized with different compositions of insulating ligands and were further grafted on the surface of nanohelices with a covalent bond. The various assemblies obtained are deposited by dielectrophoresis between interdigitated electrodes on a flexible substrate.
The flexibility, sensitivity and stability properties of the sensors are then characterized by electromechanical measurements coupled with scanning electron microscopy observations. Humidity and heat tests have also shown the efficiency of these new sensors.
This project has led to the publication of 2 theses and numerous results, some of which are confidential because they are processed in collaboration with an industrial partner.
Low cost strain sensors based on electron tunneling in assemblies of metallic nanoparticles (MNPs) are proposed as a new touch technology for flexible displays, but their sensitivity and stability are still impacted by variations in thickness, morphology and density of NPs films. With an industrial partner NANOMADE Concept, which develops a patented touch technology relying on MNPs-based resistive strain gauges, we propose to develop strain sensors based on the use of nanohelices assemblies coated with conductive nanoparticles interconnected via ligands to be advantageously used to overcome such critical points: the helical morphology exhibits enhanced flexibility that will increase the measurable range of strain; the positioning of metallic NPs with ligands on the nanohelices can be done with a high degree of precision; alignment of highly ordered wires of metallic NPs will be straightforward since they are already positioned on the nanohelices. The aim of this project is to improve the electromechanical properties of strain sensors both in terms of sensitivity as well as reproducibility and stability.
Madame Marie-Hélène Delville (Institut de Chimie de la matière condensée de Bordeaux)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
CBMN Chimie et Biologie de Membranes et de Nanoobjets
CNRS/LAAS Centre National de la Recherche Scientifique/Laboratoire d'Analyse et d'Architecture des Systèmes
ICMCB (UPR 9048) Institut de Chimie de la matière condensée de Bordeaux
Help of the ANR 548,000 euros
Beginning and duration of the scientific project: September 2016 - 48 Months