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NIST ‘Nanomechanical Mapper’ Offers New Design, Characterization Tool
Researchers at NIST (National Institute of Standards and Technology) have developed a new imaging system to map the mechanical properties of nanomaterials – at scales as small as billionths of a meter.
AFMs (atomic force microscopes) normally reveal the topography of a composite material (left) NIST's new nanomechanical mapper reveals the glass fibers are stiffer than the surrounding polymer matrix but sometimes soften at their cores. Credit: DC Hurley/
NIST’s new tool could provide researchers a cost-effective way to characterize (and even design) mixed nanoscale composites or thin-film structures.
NIST’s new DSP-RTS system (for digital signal processor-based resonance tracking system) provides a ‘nanomechanical mapper’ using custom software and electronics to process data acquired by a conventional (AFMs) atomic force microscopes. The NIST unit transforms an AFM’s normal topographical maps of surfaces into precise two-dimensional representations of mechanical properties near the surface.
The unit also has the special feature of locking onto and tracking changes in frequency as the tip moves over a surface. Mechanical properties of a sample are deduced from calculations based on measurements of the vibrational frequencies of the AFM tip in the air and changes in frequency when the tip contacts the material surface.
The images are based on measurements and interpretations of changes in frequency as a vibrating AFM tip scans a surface. Such measurements have commonly been made at stationary positions, but until now 2D imaging at many points across a sample has been too slow to be practical.
What’s in the NIST ‘Nanomechanical Mapper’ Images?
The images enable scientists to see variations in elasticity, adhesion or friction, which may vary in different materials even after they are mixed together. The NIST system, described fully for the first time in a new paper, can make an image in minutes whereas competing systems might take an entire day.
NIST materials researchers have used the system to map elastic properties of thin films with finer spatial resolution than is possible with other tools. The DSP-RTS can produce a 256 × 256 pixel image with micrometer-scale dimensions in 20 to 25 minutes. The new system also is modular and offers greater flexibility than competing approaches. Adding capability to map additional materials properties can be as simple as updating the software.
NIST’s new DSP-RTS system (for digital signal processor-based resonance tracking system) provides a ‘nanomechanical mapper’ using custom software and electronics to process data acquired by a conventional (AFMs) atomic force microscopes. The NIST unit transforms an AFM’s normal topographical maps of surfaces into precise two-dimensional representations of mechanical properties near the surface.
The unit also has the special feature of locking onto and tracking changes in frequency as the tip moves over a surface. Mechanical properties of a sample are deduced from calculations based on measurements of the vibrational frequencies of the AFM tip in the air and changes in frequency when the tip contacts the material surface.
The images are based on measurements and interpretations of changes in frequency as a vibrating AFM tip scans a surface. Such measurements have commonly been made at stationary positions, but until now 2D imaging at many points across a sample has been too slow to be practical.
What’s in the NIST ‘Nanomechanical Mapper’ Images?
The images enable scientists to see variations in elasticity, adhesion or friction, which may vary in different materials even after they are mixed together. The NIST system, described fully for the first time in a new paper, can make an image in minutes whereas competing systems might take an entire day.
NIST materials researchers have used the system to map elastic properties of thin films with finer spatial resolution than is possible with other tools. The DSP-RTS can produce a 256 × 256 pixel image with micrometer-scale dimensions in 20 to 25 minutes. The new system also is modular and offers greater flexibility than competing approaches. Adding capability to map additional materials properties can be as simple as updating the software.