sensing & sensors CMU SCS RI 16722 S2009 TH 13:30 -14:50 NSH1305

1. sensing & sensorsCMU SCS RI 16722 S2009 TH 13:30 -14:50 NSH1305 Cheow Hin Sim <csim@andrew.cmu.edu> Nanosensors for Chemical Analysis by Exploration Robots

2. Nanosensors for Chemical Analysis by Exploration Robots Nanosensors for Chemical Analysis by Exploration Robots

3. Chemical Nanosensor Needs • Chemical detectors are used in applications for • Industrial: leak detection, food quality surveillance • Environmental: air and water quality • Military: anti-terrorism applications • Aerospace: identify soil and atmospheric constituents • Various sensing techniques available: optical, electrical, mechanical… • Need to maximize the quantity, diversity, and accuracy of information extracted to achieve improved sensitivity, selectivity and stability Nanosensors for Chemical Analysis by Exploration Robots

4. Miniaturization Micro technology Nano technology • Nanostructures have high catalytic surface area: High sensitivity, selectivity and response time • Reduction in size, weight and power consumption • Multiplexing capability to distinguish multiple chemical species. Shrinking technology Rack sized measuring instrument Hydrogen sensor using palladium nanoparticles Micro Gas Chromatograph Nanosensors for Chemical Analysis by Exploration Robots

5. Principle of chemical sensing • Absorption of gas/liquid molecules • Large surface to volume ratio traps pollutants • Molecules modify physical and/or chemical properties of active layer: • Electrochemical: H-bond formation, electrostatic interaction.. • Optical: refractive index • Physical: mass.. • Transduction into a measurable signal that is proportional to analyte concentration.  Nanosensors for Chemical Analysis by Exploration Robots

6. Classification of Chemical Sensors Electrochemical reactions Mass loading Conducting pathways Heat transfer Mechanical Electrical Optical Thermal fluorescence Components of a chemical/ biological environment Refractive index Non-exhaustive list… Nanosensors for Chemical Analysis by Exploration Robots

7. Conductivity Sensors • Common sensing materials: conducting polymer composites and metal oxides and CNTs • n-type metal oxide sensor operation: • ambient O2 moelcules chemisorb onto the sensing film surface • Reducing target gas (e.g. CO) reacts with O-and release e- • Oxidizing agents (e.g. NO2) remove more e- Nanosensors for Chemical Analysis by Exploration Robots

8. Conductive Polymer Composite Conductive polymer composite 1. Vapors pass over the polymer and swelling produces a change in resistance 2. Resistance change is measured for each sensor. 3. Using pattern recognition algorithms, the data is converted into a unique response pattern. Nanosensors for Chemical Analysis by Exploration Robots

9. Array Based Sensing • Sensitivity: measure of the change in output of a sensor for a change in input. • Why do we use sensor array? • Each sensor responds to different chemicals in varying degrees • An array of sensors will give an overall response pattern that is unique for a given chemical . • How do we use sensor array? S1 = {a11 a12 a13 } S2 = {a21 a22 a23 } S3 = {a31 a32 a33 } • What if there are more sensors than unknowns? → Method of pseudo-inverses CO2 CO H2 Nanosensors for Chemical Analysis by Exploration Robots

10. Assignment (a) The figure below shows two single sensor radar plots (MoO3-HT and WO3) comparing their relative sensitivities to different gases. Identify which sensor is better for identifying NO2, CO and NH3. Explain your answer. Nanosensors for Chemical Analysis by Exploration Robots

11. Assignment (b) The figure shows the response of a sensor array to acetone. Calculate the overall sensitivity of the sensor array to acetone. Explain why a sensor array is useful for identifying a mixture of gases for this particular situation. Nanosensors for Chemical Analysis by Exploration Robots

12. Commerical Sensors NoseChipTMSensor Technology: nanocomposite sensor array weight: ~0.5 oz Power: nanowatts Cyranose 320 ArtinosSensor Technology: nanocrystalline tin oxide gradient microarray Size: 3x4 mm2power consumption@ 300oC: 1 W Nanosensors for Chemical Analysis by Exploration Robots

13. Carbon Nanotube Sensor • Hollow nanostructure and high specific surface area provides excellent sensitivities and fast response. • Can be functionalized to reversibly adsorb molecules of pollutants undergoing a modulation of electrical, geometrical and optical properties. NASA SWNT conductive gas and organic vapor detector Nanomix: Sensation Technology Nanosensors for Chemical Analysis by Exploration Robots

14. CNT Field Ionization Sensors • Different gases have a specific ionization potential. • Sharp tips of nanotubes generate very high electric field at low voltages. • No adsorption/desorption involved -> fast response Ionization gas sensor [Rensselaer Polytechnic Institute] Nanosensors for Chemical Analysis by Exploration Robots

15. Cantilever based Sensors Nanomechanical Sensor Surface Acoustic Wave Sensor • A surface acoustic wave propagates over a coated surface. • Absorption of gas molecules change in the mass of the sensor coating -> change in the resonant frequency • Cantilever is coated with a chemically selective layer. • Cantilever bends due to surface stress • Deflection of cantilever can be measured precisely by deflecting a light beam from the surface. HAZMATCAD™ by Microsensor Systems Cantilever sensor array by Concentris Nanosensors for Chemical Analysis by Exploration Robots

16. Micromachining • Microfabrication using MEMs-based technology allows minimal size, weight and power consumption. • Construction of three dimensional structures are highly desirable for chemical and electrochemical sensors and microsystems. • Enable ease of integration with electronic circuitry MEMS for rapid localized temperature control in Micro-hotplate (NIST) Nanosensors for Chemical Analysis by Exploration Robots

17. Analysis System Architecture • Pumps & valves • Fluidic interfaces Sample Acquisition Data Acquisition Analytical system Calibration, Self-check Commu-nication Sample concentration Analyte separation Chemical detection Extraction, pyrolysis Display • Chromatography • Electrophoresis • Nanosensors Environmental sampling Refresh Regeneration Nanosensors for Chemical Analysis by Exploration Robots

18. Sulfate Nitrite Nitrate Phosphate Bromide Oxalate Chloride Fluoride Chromatography • Multi-component samples are separated in specially treated separation columns before measurement with a detector. • Samples are separated by different migration speed inside column due to differing adsorption characteristics. Nanosensors for Chemical Analysis by Exploration Robots

19. µChemLabTM Preconcentrator accumulates species of interest Gas chromatograph separates species in time SAW sensor detects gas Nanosensors for Chemical Analysis by Exploration Robots

20. Space Exploration • A range of chemical sensing technologies to measure several parameters of interest simultaneously. • MEMs-based micro-sensor arrays • Reliability of sensor technologies • Harsh environment (during launching) • Calibration issues • Signal drifting • Broad inclusion into intelligent “smart” systems: • Supporting technologies: signal processing, communication.. • “Lick and stick” technology (ease of application) • Take advantage of quantum properties of materials for ultra-sensitive detection. • CNTs, nanowires,nanopores.. “Lick and stick” smart leak detector Nanosensors for Chemical Analysis by Exploration Robots

21. AstroBioLab for Mars Exploration ExoMars Rover • Mobile laboratory that uses a suite of in situ instruments: Mars Organic Detector and Oxidant detector, micro-capillary electrophoresis analyzer. • Target compounds are amino acids and Polycyclic Aromatic Hydrocarbons • Electronics designed for Martian ambient survivability (-145 to 100oC) • Low power consumption with broad chemical extraction ability. Nanosensors for Chemical Analysis by Exploration Robots

22. Mars Organic Detector • Uses sublimation at Mars ambient pressure and temperatures to release organic components of retrieved samples. • Highly sensitive fluorescent detection, detects presence/ absence of amino acids and PAH • Interfaced with microchip-based capillary electrophoresis for identification of amino acids Specifications: Mass:~ 2 kg Power: 24 W Size: 145 x 193 x 112 mm Nanosensors for Chemical Analysis by Exploration Robots

23. Mars Oxidant Detector • Test the Martian samples and environment for their ability to degrade organic compounds through oxidation • Monitor reaction with well-characterized reactants over days/weeks exposure. • The chemical state is monitored by measuring electrical resistivity via a chemiresistortransducer. Mars Oxidant Instrument (MOI) sensor arrays configured into a soil cup Nanosensors for Chemical Analysis by Exploration Robots

24. UK team builds robot fish to detect pollution Fri Mar 20, 2009 6:11am EDT LONDON (Reuters) - Robot fish developed by British scientists are to be released into the sea off north Spain to detect pollution. If next year's trial of the first five robotic fish in the northern Spanish port of Gijon is successful, the team hopes they will be used in rivers, lakes and seas across the world. The carp-shaped robots, costing 20,000 pounds ($29,000) apiece, mimic the movement of real fish and are equipped with chemical sensors to sniff out potentially hazardous pollutants, such as leaks from vessels or underwater pipelines. They will transmit the information back to shore using Wi-Fi technology. Unlike earlier robotic fish, which needed remote controls, they will be able to navigate independently without any human interaction. Rory Doyle, senior research scientist at engineering company BMT Group, which developed the robot fish with researchers at Essex University, said there were good reasons for making a fish-shaped robot, rather than a conventional mini-submarine. "In using robotic fish we are building on a design created by hundreds of millions of years' worth of evolution which is incredibly energy efficient," he said. "This efficiency is something we need to ensure that our pollution detection sensors can navigate in the underwater environment for hours on end." The robot fish will be 1.5 meters (nearly 5 feet) long -- roughly the size of a seal. Nanosensors for Chemical Analysis by Exploration Robots

25. References • http://www.eetimes.com/showArticle.jhtml?articleID=212000236 • Liu H., Kameoka J., Czaplewski D.A., Craighead H.G., “Polymeric Nanowire Chemical Sensor”, Nano Lett., 4(4), 2004. • Sugiyasu K. and Swager T.M., “Conducting-Polymer-Based Chemical Sensors: Transduction Mechanisms”, Bull. Chem. Soc. Jpn., 80(11), 2074-2083 (2007). • http://www.technologyreview.com/Nanotech/19003/ • http://www.sandia.gov/mstc/technologies/microsensors/micro-chem-lab.html • S. Joo and R. B. Brown, “Chemical Sensors with Integrated Electronics”, Chem. Rev. 108 (2), 2008 • http://www.specs.com/products/Kamina/electronic-nose.pdf • K. Arshak, E. Moore, G. M. Lyons, F. Harris and S. Clifford, “A review of gas sensors employed in electronic nose applications”, Sensor Review 24 (2), 181-198, 2004 • NASA Ames research Center, http://www.nasa.gov/centers/ames/research/2007/mars_sensor.html Nanosensors for Chemical Analysis by Exploration Robots

26. References • J. Bryzek, S. Roundy, B. Bircumshaw, C. Chung, K. Castellino, J. R. Stetter and M. Vestel, ”Marvelous MEMs”, IEEE Circuits & Devices Mag., March/April 2006 • A. Modi, N. Koratkar, E. Lass, B. Wei & P. M. Ajayan, “Miniaturized gas ionization sensors using carbon nanotubes”, Nature 424, 171 (2003). • C. Hagleitner, A. Hierlemann, D. Lange, A. Kummer, N. Kerness, O. Brand & H. Balters, “Smart single-chip gas sensor Microsystems”, Nature 414, 293 (2001). • N. V. Lavrik, M. J. Sepaniak, P. G. Datskos, “Cantilever transducers as a platform for chemical and biological sensors”, Review of Scientific Instruments 75 (7), 2229 (2004) • Nanomix, http://www.nano.com/ • Concentris, http://www.concentris.ch/ • Microsensor Systems Inc., http://www.microsensorsystems.com/aboutus.html Nanosensors for Chemical Analysis by Exploration Robots