An ellipsometer can be used to measure the thickness.

As ellipsometer facility is not available here.. any other sugestion

You can measure through SEM, just look on the cross-sectional area.

In addition to ellipsometry or by cross-sectional SEM, spectral reflection is another option. What is the range of film thickness are you looking to measure? Are these free standing films or coatings on a substrate? If these are coatings on a substrate, other methods are also possible.

There are several ways to measure the thickness of a film.

1. Profilometer (stylus based ).

2. Optical Profilometer.

3. Eddy current based sensor elcometer.

http://www.elcometer.com/coating-thickness-gauge

4. Cross section SEM.

5. Micrometer.

There is plenty of literature available that tells the techniques and comparisons of film thickness measurement and their comparison. A paper is mentioned below:

http://www.sciencedirect.com/science/article/pii/0040609085902731

For measuring film thickness, it is not mentioned whether it is free standing film or it is on some substrate like iron or plastic. For measuring film thickness on some surface, we use coating thickness meter having accuracy of +/- (1%+0.1 μm) relative to reference standard with measurement range from 0-120 mils having resolution of 0.01 mils. 

Thanks a lot for your valuable sugestions and discussion

I measured polymer blend films with the help of micrometer. You can use any available instrument for the said purpose. Most of fellows are also using screw gauge for the same purpose.

SEM

Metricon prism coupler is a better instrument to measure thickness quickly and accurately which is better than ellispometer if the film is a free standing one. If the film is on a substrate a simple frequency counter can be used while coating the film itself.

There are many methods to check the plastic film blends like DSC, XRD, FT-IR, POM, SEM, TEM and others

Through Differential scanning calorimetre analysis, we can find out  the polymer blend film is miscible blend or not through Glass transition temperature(Tg). Other way universal tensile tester to test the physical properties(strength) of the blend film.

While asking a question, always be explicit in providing full information so that specific answers can be given. Secondly, to what accuracy you want to measure the sample thickness? This point is also important. Since you can try two instrument for this purpose, use both and measure the polymer film thickness and see the difference.

good luck

Dear Ranganathaiah and others, Thanks a lot for your valuable sugestions 

Nanoindentation can be used to measure the film thickness. Effect of the substrate during indentation give the idea about approximate film thickness. In my work, I have measured the PMMA film thickness on silicon substrate applying nanoindentation. For more details go through below links. 

http://onlinelibrary.wiley.com/doi/10.1002/app.43532/full

http://www.sciencedirect.com/science/article/pii/S0032386116301227

Another reference.

Nanoindentation Anthony c Fischer Scripps