Isaline Recloux

Optical fibre NO2 sensor based on lutetium bisphthalocyanine in a mesoporous silica matrix

In this article, we describe a NO2 sensor consisting of a coating based on lutetium bisphthalocyanine (LuPc2) in mesoporous silica. The sensor exploits the absorption spectrum change of this material which strongly and reversibly decreases in contact with NO2. NO2 is measured by following the amplitude change in the reflected spectrum of the coating deposited on the tip of a silica fibre. As diffusion of NO2 in LuPc2 is slow, the response time could be slow. To reduce it, the active molecules are dispersed in a mesoporous silica matrix deposited by a sol-gel process (Evaporation Induced Self Assembly) avoiding the formation of large crystals. Doing so, the response is fairly fast. As the recovery is slow at room temperature, the recovery time is reduced by exposure to UV light at 365 nm. This UV light is directly introduced in the fibre yielding a practical sensor sensitive to NO2 in the ppm range suitable for pollution monitoring.

Development of mesoporous sol–gel films for antifingerprint applications on glass

AbstractMesoporous films were synthesized by specific sol–gel route, including the use of surfactant molecules acting as templating agent through the evaporation induced self-assembly process. Controlled mesoporosity of the film is obtained by the thermal removal of the templating agent. In this work, the mesostructure of the sol–gel layer is used as reservoir for active enzymatic molecules providing antifingerprint coating. The mesopore size and their configuration were designed to assure a good impregnation by lipases. The coatings were applied on glass. The influence of the deposition process and the composition of the sol–gel on the structure of the mesoporous film was investigated. The film morphology was characterized by scanning electron microscopy and water adsorption/desorption isotherms recorded with a quartz crystal microbalance. The stability of the sol–gel solution was assessed by rheological measurements. The efficiency of the combination of mesoporous film and the enzymatic solution was determined in terms of antifingerprint properties using an artificial sebum. Mesoporous sol–gel film is used as reservoir for active enzymatic biomolecules to provide antifingerprint coating. Mesoporous structure is obtained by the sol–gel method using the evaporation induced self-assembly process. Different parameters (thickness of coating, concentration in templating agent, etc.) were studied to manage and adapt the size and the structure of the mesopores in order to obtain an active coating.HighlightsDesign of mesoporous sol–gel films using evaporation induced self-assembly process.Influence of the thickness, deposition method, and templating agent/precursor molar ratio on the mesoporosity.Evaluation of antifingerprint properties of the sol–gel films impregnated with enzymes.