I'm wondering whether the liquid states of sugars like sucrose or trehalose Newtonian fluids. It is often said the aqueous solution of sugar or salt is Newtonian. But not sure about the melt of pure sugar. Any response would be appreciated.
It is quite simple to find out:
Solution 1: take a viscometer with pallets from any "friendly" laboratory if you don't have and plot the torque vs. speed. If the graph passes through the origin, you have a Newtonian fluid.
Solution2: take any toy electrical motor, firmly attach a small plate to the axis, use an amperemeter in series with it to find the current intensity and power the motor with a supply like the one you have in toy trains (measure the tension before to know how much you input for each position of the knob). Plot tension vs. intensity (or power which is U*I) and if it is passing through the origin, you have a Newtonian fluid.
For calibration you can use honey. Of course, the viscosity is highly dependent on temperature.
I hope my electricity knowledge is not too rusty but I think the second solution is correct.
We often use pure glucose (or concentrated glucose solutions) in our experiments and they all exhibit purely newtonian behavior. However, their viscosity can be treacherous to measure in a rheometer due to water evaporation, viscous heating (which then decreases the viscosity considerably), etc. However, I do not know exactly for sucrose or trehalose, but at first hand, I would presume them to be Newtonian.
Thanks, Manole and Bruno. Your suggestions and answers are very helpful.
The aqueous solutions of threalose and maltose at low concentrations behaves as a newtonian liquid. But these mixtures at high concentrations shows nonnewtonian reology behavior.