Hi, I am a Bachelor Student of biomedical engineering and I have a question regarding the complex compressive modulus. I am really a newbie in this field, hopefully somebody can help me. I have measured four different hydrogel films to compare with the same conditions using a dynamic mechanical analyzer (DMA, measured in compression mode with a sinusoidal deformation of constant amplitude, ε=0.1%). Now the results show that the materials that have the highest storage modulus also have the highest tan δ, which is a bit confusing to me as I though when measuring viscoelastic materials with a DMA it should always the other way round (so the ones with the highest E' should have the lowest tan δ). I am attaching E', E'' and tan delta graphs so you see what I mean. Thank you!