Is it possible to understand the structural phases (alpha, beta, gamma, delta) of PVDF thin films by looking the surface morphology of grains using AFM images . Will there be any particular grain structure for particular phase? And spherullite type structure corresponds to which phase? How do we know whether the film is in a single phase or a mixture of phases?
PVDF firstl of all needs a heat treatment to convert from alpha phase to beta phase. this is well known.
AFM will be useful for studying surface morphological features, and I doubt if it can tell you about the phases.
Simple XRd technique may be more useful.
After converting from alpha to beta phase, and appropriate treatment (stretching, and electrical poling), it becomes piezoelectric.
Instead of AFM, I feel PFM can be a more useful technique, because the beta phase can become a good piezoelectric, and the piezo response can be studied using a PFM.
If the prepared material has a mixture of the two phases, then probably PFM can reveal some useful information.
K. Sreenivas
Dear Pramod,
In my knowledge, in trapping mode if you give input signal and measure the output in signal form, than by changing the phases of the particle of the surface, the output signal will change its phase. So you can only observe change in the phases but not physically measure it.
@Pramod: I can feel your queries since you are talking about PVDF thin films. My very close observation is: in principle by AFM also possible to distinguish between alpha and beta/gamma phases. However more conclusive techniques would be ATR-FTIR or Grazing Incidence FTIR (ref: one of my article on PVDF thin film:Langmuir, 2012, 28 (28), pp 10310–10317). Note that normal XRD is never conclusive for phase identifications of PVDF, even for bulk films, in particular to distinguish between beta and gamma phase. You can read my comment article on this topic (The Journal of Physical Chemistry B 115 (35), 10567-10569). I hope these information might be useful for your work.
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