A sensing composite structure-based Microsystem devoted to the selective measurement of benzene, toluene and xylenes. – CAPBTX

The CAPBTX project is devoted to the implementation of a gas sensing microsystem permitting a selective metrology of five homologous aromatic compounds : benzene, toluene and xylene (ortho, para, meta). Our strategy is based on the constitution of a judicious composite sensing structure involving macrocyclic molecules (phthalocyanines, porphyrins, corroles) conditioning great affinities with aromatic gases in detection. In order to reach a selective detection, we intend to study the development of an optimized multi-layers sensing structure : functionalization of the macrocycles sensing sites, immobilized in porous matrix made of polymers and/or nanocarbons, should create constraints for adsorption of aromatic gaseous compounds. We intend to obtain several macrocyclic materials provided with various steric, electronic, hydrophobic and lipophobic properties and associated with important disparities in the interactions of adsorption with the five target aromaticgases.
Three complementary transducing modes will be implemented:
- Quartz Coated Microbalance (QCM) involving bulk acoustic waves with a resonance frequency associated to the mass of gas adsorbed on the sensing layer,
- Measurement of the electric conductivity of the sensing layers interacting with gases. The information delivered by the device is associated to the modulation by gases of electrical parameters such as the concentration, and/or the mobility of free charge carriers, the dielectric constant,
- dielectric answer of a material to a gas subjected to a microwave-type electromagnetic field.
The transducing modes will be tested in order to obtain a finalized structure optimizing the metrological parameters and, specifically in order to increase the selectivity of the detection.
The selective detection will be reached by the association of the sensing macrocyclic structures/transductors able to give enough complementary informations towards the five target aromatic compounds.

This project involve four laboratories associated with complementary competences :
- LASMEA (UMR 6602 CNRS/Université Blaise Pascal), from scientific department ?ST2I? with an international level in the field of microsystem gas sensor,
- l’ICMUB, (UMR 5260 CNRS/Université de Bourgogne) from department ?Chimie? with an international level in the field of macrocyclic molecules synthesis ,
- le LMI (UMR 6002 CNRS/ Université Blaise Pascal) from department ?Chimie? with an international level in the field of nanocarbons,
- l’ICB (UMR 5209 CNRS/ Université de Bourgogne) from department ? Nanosciences ? with an international level in the field of microwaves,
Three partners (LASMEA, l’ICMUB et l’ICB) structured the ANR POLL-CAP project (2006-2009) devoted to the selective detection of polluting gases ozone and nitrogen dioxide by mean of specific microsystem gas sensors. The laboratories involved in the present CAPBTX project are well aware of every aspects of metrology by mean of semiconductor gas sensors as all common scientific publications and the two patents attest it in the context of the past POLL-CAP ANR project.