AFM topography/Elasticity imaging of polymer hydrogel pattern on Silicon substrate
Height-Topographic | Amplitude-Elasticity | Phase- Error |
Height-Topographic 3D | Amplitude-Elasticity 3D | Phase- Error 3D |
Tuning forks have very high Q factors which correspond to a very sharp frequency spectrum allowing phase feedback to be employed to monitor topographic alterations. Thus, the amplitude of the oscillation of the cantilever, which is not the feedback signal in this methodology as is the case in beam bounce technology, can now be used as a separate and independent channel to monitor the energy dissipation of the cantilever as a function of material elasticity. In addition, tuning fork feedback does not exhibit jump to contact and adhesion ringing and therefore elasticity and adhesion with the tuning fork feedback is the best monitor of such material properties.
The following line profiles (correspond to marked lines above) show the polymer elasticity compared to silicon surface (Middle) where the Amplitude at the polymer area is 150 mV compared to 25 mV for the silicon area. The profile at the bottom plot shows the same value of Phase signal at both polymers and silicon regions which corresponds to the Error signal used for feedback of 250 mV. Top plot shows the correlated topographic Height profile.
WSxM software has been used for image processing of the pictures above: I. Horcas et al. Rev. Sci. Instrum. 78, 013705 (2007)
5x5 microns AFM_Height Image of PPKTP crystal |
Correlated PFM_Phase image |
Correlated PFM_Amplitudeimage |
AFM_Height 3D Presentation |
PFM_phase 3D Presentation |
PFM_Amplitude3D Presentation |
Height and PFM_phase 3D Collage Presentation |
Height and PFM_Amplitude 3D Collage Presentation |
Transistor NSOM Imaging | ||||||||||||
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Polymer Blend | ||||||||||||
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Nickel incorporated in polymer matrix (see below for notes)
4.5 x 4.5 micron AFM Image z-range: 20nm |
3D image |
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1.5 x 1.5 micron AFM Image z-range: 12nm |
3D image |
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0.55 x 0.55 micron AFM Image z-range: 7nm |
3D image |
Imaging conditions:
In the 4.5 x 4.5 micron image, it can be clearly seen, that the polymer surface is very flat, but it consists of two distinct phases. There are islands which are 5 – 8 nm higher than the lower parts.
The same features are visible in the 1.5 x 1.5 micron image. In addition a granular structure of both the islands and the lower surface is visible in this image. This granules can have a connection to the incorporated Nickel, but it is also possible, that this granules are connected to the way the polymer film was fabricated.
The 0.55 x 0.55 micron image shows again the granular structure of both the islands and the lower surface. The granules are 20 – 50 nm in diameter and 0.5 – 2 nm high.There seems to be no difference in granularity between the islands and the lower polymer surface.
Only Nanonics is able to produce AFM images with such a large z scan range.
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