Iterative control approach to high-speed force-distance curve measurement using AFM: Time-dependent response of PDMS example

Kyong Soo Kim, Zhiqun Lin, Pranav Shrotriya, Sriram Sundararajan, Qingze Zou

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

Force-distance curve measurements using atomic force microscope (AFM) has been widely used in a broad range of areas. However, currently force-curve measurements are hampered the its low speed of AFM. In this article, a novel inversion-based iterative control technique is proposed to dramatically increase the speed of force-curve measurements. Experimental results are presented to show that by using the proposed control technique, the speed of force-curve measurements can be increased by over 80 times-with no loss of spatial resolution-on a commercial AFM platform and with a standard cantilever. High-speed force curve measurements using this control technique are utilized to quantitatively study the time-dependent elastic modulus of poly(dimethylsiloxane) (PDMS). The force-curves employ a broad spectrum of push-in (load) rates, spanning two-order differences. The elastic modulus measured at low-speed compares well with the value obtained from dynamic mechanical analysis (DMA) test, and the value of the elastic modulus increases as the push-in rate increases, signifying that a faster external deformation rate transitions the viscoelastic response of PDMS from that of a rubbery material toward a glassy one.

Original languageEnglish (US)
Pages (from-to)911-920
Number of pages10
JournalUltramicroscopy
Volume108
Issue number9
DOIs
StatePublished - Aug 2008
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Instrumentation

Keywords

  • High-speed force-distance curve
  • Iterative learning control
  • PDMS
  • Scanning probe microscopy
  • Time-dependent material properties

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