Hello everyone, I am trying to measure the rheological properties of my protein based hydrogel at 10°C using cone and plate measure system (20mm diameter, 56um gap) I did amplitude sweep and frequency sweep to determine the LVE range of my hydrogel.
When I run the amplitude sweep experiment from 0.1-10 % strain with 0.1 rad/s frewuency, I did not get the G’ and G” values in measuring strain range (0.1-10% strain). The values were out of selected rage. I do not know why it happens. When I used the parallel plate measuring system (20mm diameter, 1000mm gap), I got the same results. In frequency sweep experiment, I had values in measuring range. Can anyone help me to understand why I did not get meaningful values of stain % during amplitude sweep?
I attached the graphs, left amplitude sweep has the stain % which I used during experiment, right graph showed automatic scale for stain %.
My sample is protein based soft hydrogel, so I cannot use high strain and frequency values. I also need to run experiment at 10°C.
Thanks
Hi Aamna,
maybe you should try a larger cone diameter, like 50 mm, for higher sensitivity. Also try measuring at 10 rad/s. Together they will give a little bit more torque and therefore maybe better results.
Frank Baten
Thanks Frank
I will try this to get some better results. But my sample is soft hydrogel so I am worried that 10 rad/s will break it.
If you want to know the LVE range then you need to break the structure. The LVE range is dependent on what frequency you use but if you think 10 rad/s is too high than you could try some frequencies in between 0.1 and 10 rad/s.
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