Atomic force microscope with integrated heater actuated using Lorentz force.
nano-films and nano-composites are used in a wide variety of
applications from food packaging to sports equipment to automotive and
aerospace applications. Thermal analysis is routinely used to analyze
materials for these applications, but the growing trend to use
nanostructured materials has made bulk techniques insufficient.
recent years an atomic force microscope-based technique called
nanoscale thermal analysis (nanoTA) has been employed to reveal the
temperature-dependent properties of materials at the sub-100 nm scale.
Typically, nanothermal analysis works best for soft polymers.
Researchers at the University of Illinois at Urbana-Champaign and Anasys
Instruments, Inc. have now shown that they can perform nanoscale
thermal analysis on stiff materials like epoxies and filled composites.
new technique lets us measure temperature and frequency-dependent
properties of materials rapidly over a wide bandwidth,” noted William
King, the College of Engineering Bliss Professor in the Department of
Mechanical Science and Engineering at Illinois, who led the research.
The technique works by flowing a current around the U-shaped arms of a
self-heating atomic force microscope (AFM) cantilever and interacting
that current with a magnetic field. The magnetic field allows the
tip-sample force to be modulated right near the tip of the AFM.
are able to achieve nanometer-scale force control that is independent
from the heating temperature,” according to Byeonghee Lee, first author
of the paper.
nanothermal analysis has struggled with highly filled, highly
crosslinked materials and sub-100 nm thin films. This new technique has
allowed us to reliably measure and map glass transitions and melting
transions on classes of materials that were previously very
challenging,” said Craig Prater, chief technology officer at Anasys
Instruments and co-author on the paper.
research was performed in King’s Nanoengineering Laboratory and at
Anasys Instruments. King is also affiliated with the Department of
Materials Science and Engineering, the Department of Electrical and
Computer Engineering, the Beckman Institute for Advanced Science and
Technology, the Micro and Nanotechnology Laboratory, and the Materials
Research Laboratory, all at the University of Illinois. The research was
sponsored by the Air Force Office of Scientific Research and the
National Science Foundation.
Magnetic Actuation of a Heated Atomic Force Microscope Cantilever using Lorentz Force