Polymers are generally damaged easily under high-voltage SEM due to low thermal conductivity. Although some papers are indicating that the accelerating voltage for PMMA can be as high as 20kV, I wanted to ask what is the maximum voltage that PMMA/GNP can tolerate.
Hi,
You should take into account that heating is caused by the dissipated power P=I*U. Reducing the beam current (smaller aperture) could be one step. If a layered film on a substrate of good electrical and thermal conductivity ist considered, a high voltage would shift most of the excitation out of the PMMA, thus reducing the damage. Using a low energy (FESEM can operate at 200 eV) will excite the PMMA only but reduce the dissipated power. The optimum settings will depend on your needs (resolution).
The best practical resolution in FE-SEM usually can be reached at accelerating voltage of about 1-3 kV. Higher voltage just increases the interaction volume via increasing the depth of electrons penetration into the sample surface and actually spoils the resolution. 20 or 30 kV is used for EDX or some "exotic" applications, e.g. to localize some contrast structures under a covering layer. It has no advantages in routine imaging.
Please read this discussion:
https://www.researchgate.net/post/SEM-accelerating-voltage
Good luck!
In our work we got good results and very informative SEM images in the case of PMMA/PC/GO polymers blends. Accelerating voltage mostly gives rough imgaes owing to upsurge in electrons penetration @ sample surface as explained by Denis Korneev
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