NanoPiC project aims at creating innovative piezoelectric materials with enhanced properties, from ceramic-polymer structured composites. The structuration at different scales (from micron to nanometer) will be performed by thin film etching of BNT ceramic. The choice of these ceramics is based on the twofold aspect of non-toxicity (lead free) and the high piezoelectric properties (d33 = 80/120 pm/V). The passive or active fluorinated polymer (PVDF or PVDF-TrFe) will be incorporated by grafting from ceramic surfaces in order to increase the interfacial cohesion between the two materials. In polar crystalline phase, the fluoropolymers present the advantage to have a high piezoelectric coefficient compared to other polymer materials (|d33| = 20/30 pC/N). The combination of processes such as ceramic etching and polymer grafting for the fabrication of structured composites is an original and innovative approach.
In the case of PVDF, the structuration of domains from microns to nanometers present a high interest on the polymer crystalline structure and may imply a phase change (no polar/polar) induced by the confinement. The polymer initially passive can then become active.
The piezoelectric characterization of composites will be investigated at the macroscopic scale in order to probe the global piezoelectric answer of the material. In this case, the poling parameters (direction of the electrical field, time and temperature) will have a key role and will allow a parallel or anti-parallel poling of ceramic or polymer domains, i.e. a compensation or addition of piezoelectric properties. In addition, local piezoelectric properties will be performed by PFM (Piezoelectric Force Microscopy) to evaluate the impact of the size (micro- or nano-metric domains) and of the environment (for instance in the case of ceramic domain, the influence of passive or active polymer incorporation, influence of grafting...) of ceramic and polymer domains on the piezoelectric performances. The understanding of multi-scale piezoelectric behaviors of these structured composite materials is simultaneously a fundamental scientific challenge, and an innovative means to widen the scope of utilization of these materials for applications in pMUT (piezoelectric Micro machined Ultrasonic Transducers) area.
Madame Sophie Barrau (Unité Matériaux et Transformation)
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.
UCCS Université d'Artois - Unite de catalyse et Chimie du solide
UMET Unité Matériaux et Transformation
IEMN Institut d'Electronique de Microelectronique et de Nanotechnologie
ICGM Institut Charles Gerhardt Montpellier
Help of the ANR 500,579 euros
Beginning and duration of the scientific project: - 48 Months