The Lorentz Contact Resonance (LCR) imaging mode further enhances the capabilities of the afm+ and nanoIR systems. LCR allows rapid broadband nanomechanical measurements over a range of temperatures, identifying key sample measurement contrasts, and allowing precise probe placement for subsequent chemical or thermal analysis with nanoscale resolution.
How it works
Because there are no moving parts actuating the cantilever, Lorentz Contact Resonance provides a very clean excitation over broad frequency ranges (bottom plot). Piezo drive schemes (top plot) can excite many spurious resonances that interfere with contact resonance measurements and interpretation of the results.
Mechanical property insights
Left: A selection of LCR nanomechanical spectra obtained on different polymers. Different polymers can be distinguished on the basis of position and/or height of contact resonances in the LCR spectra.
Multi-component samples can be imaged at multiple frequencies, identifying and imaging each component individually. The Analysis Studio software can then be used to create an RGB overlay image.
Three color mechanical map of wood cells. This composite image was made by overlying the LCR amplitudes collected at three different contact resonances. These resonances were selected to highlight the varying ratios of the lignin and cellulose which compose the sample.
AFM image (left) and a series of Lorentz Contact Resonance mechanical spectra (right) on a blend of polystyrene (PS) and low density polyethylene (LDPE). LCR spectra clearly distinguish the PS and LDPE by the positions and amplitudes of the resonant peaks.
LCR provides high resolution maps of material components in heterogeneous materials.
AFM image (left) and LCR composite image (right) of a polymer blend. This image was created by combining LCR amplitude images at three different contact resonances to highlight the distribution of the blend components. Lee et. al., Nanotechnology 2012, 23, 055709.