Probing viscoelasticity of nanometer thick self-assembled layers

Srinivas Tadigadapa, Hwall Min, Ping Kao

Research output: Chapter in Book/Report/Conference proceedingConference contribution


In this paper, we will demonstrate the applications of micromachined bulk acoustic wave resonators for the systematic investigation of adsorbing films and nanomaterials on their surface. By careful design and development of glass etching technology, we have successfully micromachined quartz shear wave resonator arrays with frequencies in the range of 60 to 90 MHz (25-18 μm in thickness) with quality factors exceeding 30,000. The response of the resonators to various surface loads has been carefully modeled assuming a dynamically forming viscoelastic film under a fluidic overlayer. Making systematic measurements of the resonator frequency and quality factor response at the fundamental and third overtone and using nonlinear model fits, we have deduced the density, thickness, viscosity, and elasticity of various globular proteins adsorbing on hydrophobic, hydrophilic and charged hydrophilic surfaces. Furthermore, we will show that the proposed method is sensitive enough to study the copper underpotential deposition (UPD) and stripping in 1 mM CuSO 4 + 0.5 M H2SO4 solution. The results provide a comprehensive characterization of the viscoelastic properties of the electrical double layer in the copper UPD system through the use of high frequency QCM resonators and demonstrate a highly useful approach for achieving a deeper understanding of aqueous electrochemical systems.

Original languageEnglish (US)
Title of host publicationIEEE SENSORS 2012 - Proceedings
StatePublished - Dec 1 2012
Event11th IEEE SENSORS 2012 Conference - Taipei, Taiwan, Province of China
Duration: Oct 28 2012Oct 31 2012

Publication series

NameProceedings of IEEE Sensors


Other11th IEEE SENSORS 2012 Conference
Country/TerritoryTaiwan, Province of China

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering


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