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IMM Roma. Mass and Conductivity sensors based on Nanostructured conjugated polymers coating. E. Zampetti , S. Pantalei, A. Macagnano, A. Bearzotti IMM-CNR Rome, Via del fosso del cavaliere 100, 00133 Rome, Italy. Venditti, I. Fratoddi, M. V. Russo
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IMM Roma Mass and Conductivity sensors based on Nanostructured conjugated polymers coating E. Zampetti, S. Pantalei, A. Macagnano, A. Bearzotti IMM-CNR Rome, Via del fosso del cavaliere 100, 00133 Rome, Italy. Venditti, I. Fratoddi, M. V. Russo Chemistry Department, University of Rome La Sapienza, p.le Aldo Moro 5, 00185, Rome, Italy Perugia, 12-15 June 2007 E-mail: emiliano.zampetti@imm.cnr.it
Outline Transducers Nanostructured Materials: the active area improvement. Nanostructured Material Characterizations by interdigitated and QCM transducers. Conclusions
Transducers : Interdigitated structures Quartz Crystal Microbalance 30mm 18mm 18mm 30 mm Two interdigitated sensors (differential measurement) with integrated heater Multichannel QCM2 Coated with Nanostructured Polymer Characteristics: Characteristics: Plate: Quartz F0: 10-40 MHz Pad: Cr/Au Ф: 8-14 mm Thickness: 60-120 um Wafer: Si/SiO2 Finger: 40 Metal: Cr 100 nm Dimensions: 20μm / 20μm Length: 5600μm Humidity is an important parameter in many sensor application fields: (bio medical, environmental, food) 2 S. Pantalei, E. Zampetti, A. Macagnano et all. “A Multichannel Quartz Based Electronic Nose”, EUROSENSORS XX, Vol 2, (2006) 416-417.
Materials: the active area improvement POLIFENILACETILENE (PPA) CO-POLI(FENILACETILENE/2-IDROSSIETILMETACRILATO) P(PA/HEMA) Synthesis1 by Bottom Up approach Synthesis1 by Bottom Up approach 200 nm 300 nm PPA (nano-beds) PPA/HEMA (nano-beds) 1 Sensors and Actuators B, in press (October 2006) Synthesis of conjugated polymeric nanobeads for photonic bandgap materials I. Venditti, R. D'Amato, M. V. Russo, M. Falconieri
Response vs. humidity Vp=1 V RH step: 2.5% every 300 s RH stop: 1000 W/D Elected coating P(PA/HEMA) F0: 20 MHz Res. ≈ 0.2 ng/Hz Dep. MPPA= Dep. MassPPA/HEMA Nitrogen carrier
Hysteresis and Reproducibility Interdigitated sensors need of thickness measurement (1 and 2 are different) Interdigitated sensors are affected by the hysteresis phenomena more than mass sensors The interdigitated sensor performance changes in the whole range (sensitivity, response) The mass sensor response is affected by other VOCs “QCM sensor with integrated interdigitated sensor may be used”
Thickness effects Butterworth Van Dike Model ( I° order) L: Mass loading R: Viscosity coefficient C: Elastic coefficient No viscoelastic effects due to the coating. According to Sauerbrey: Frequency shift vs. thickness fq: resonant frequency mf:surface density ρq: quartz density (act.area S)
Acoustic Stiffness Coated: shift 12 KHz Uncoated Coated: shift 75 KHz Coated: shift 35 KHz Viscoelastic effects
Adsorption phenomena: thickness effects t5 RH% Response t1 t5 t5 >> t1 t1
Conclusions Conductivity and Adsorption measurements have been performed. Acoustic stiffness, Thickness are very important parameters in sensorial application. Nanostructured PPA and P(PA/HEMA) are excellent chemical interactive materials for humidity sensors. Future outlooks Functionalization of the Nanostructured PPA or P(PA/HEMA) to increase the VOC sensitivity. A hybrid (conductivity, mass) sensor based on P(PA/HEMA) may be used in Artificial Sensorial Systems (Electronic Nose).
Gli autori Antonella Macagnano Iole Venditti Maria Vittoria Russo Simone Pantalei Andrea Bearzotti Emiliano Zampetti ringraziano per la cortese attenzione E-mail: emiliano.zampetti@imm.cnr.it