RingElectrode QCM Devices for Uniform Mass Sensitivity Distribution

1
Ring-Electrode QCM Devices for Uniform Mass
Sensitivity Distribution

• Name Justin T. Stewart
• Level Senior
• Number of Semesters Participated 1
• Date of Submission December 20th, 2008
• Advisor Dr. Venkat R. Bhethanabotla, Ph.D.
• Department Chemical Biomedical Engineering

2
Fundamental Concepts
Sauerbrey Equation
?f Change in Frequency ?m Change in Mass f0
Resonant Frequency A Active Piezoelectric
Area ?q Density of Quartz ( 2.628
g/cm³) µq Shear Modulus (AT Cut
2.947 x 1011 g/cms²) ?q Acoustic Wave
Velocity (AT Cut 3340 m/s) Cf Mass
Sensitivity (MHzm2/kg)

• Contacting Medium
• interacts mechanically with resonator
• electromechanical coupling in quartz
• mechanical properties of medium
• reflected in electrical properties of
• resonator

3
Design Apparatus
Plasma Sterilizer
Spin Coater

• Mass Measurements at or near
• surface
• Thin film characterization
• Measures resonant frequency
• and resistance
• Relates Frequency Shifts to
• changes in Mass

Novel Micro-valve Positioner
Thermal Evaporator
4
Experimental Results (Single Ring)
Fabricated Single Rings
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Experimental Results (Concentric Ring)
Fabricated Concentric Rings
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Acknowledgements

• University of South Florida College of
  Engineering
• Dr. Venkat Bhethanabotla
• Professor of Chemical Engineering, Sensors
  Research Lab
• Dr. Vinay Gupta
• Professor of Chemical Engineering, Polymeric and
  Interfacial Research Lab
• Dr. Sylvia Thomas
• Assistant Dean, Diversity and External Affairs
• Bernard Batson
• NSF/IGERT Program Director, Academic Services
• Anthony Richardson
• Graduate Student, Sensors Research Lab
• Mandek Richardson
• Graduate Student, Sensors Research Lab