As I know, gel is a liquid like behavior and viscous. However, it is basically cross-linked between liquid and gellator, such as water + PVA hydrogel. Also, I've heard that not all gel is viscous.
In this case, if the mixture has very low viscosity, how can I know that the mixture is a gel?
Is there any method to know about it?
Hello Myoungjin,
this is an interesting question as it really depends what you mean by a gel. Gels are normally considered elastically dominated and independent of frequency in an oscillation frequency sweep. However I wonder if you’re asking if a sample is a gel in that it has elastic properties at low frequencies? Eg it is a viscous liquid when touched but weakly gel like when at rest, like a handsanitizer?
If so, you would run an oscillation frequency sweep in the linear strain region down to low frequencies and see whether the phase angle is falling below 45degrees at low frequencies.
If you are running a gelation Test and are trying to determine when the sample has just gelled up. This can be done by running multiple frequencies continually through the test and seeing when the phase angle becomes independent of frequency.
hope this helps.
regards
Phil
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