The liquid that I am trying to float on top is an acrylic monomer. It doesn't dissolve in water, so water based solutions will work. I have not tried a sucrose solution but I did use a 22% salt water solution and it was actually much worse than the glycerin as far as pulling up into the acrylic resin. I have been going by the average distance the bottom liquid pulls into the upper liquid before the tension breaks and for the glycerin its 1-2mm while the salt water was 3-5mm. This is what lead me to believe it was a problem with surface energy.
My latest test is to mix in hand soap to the glycerin and salt water mixtures as a sulfactant, but it takes some time for the solution to become clear after the soap clouds it up, so I haven't yet been able to test it.
Do you think a sucrose solution would be better somehow? My understanding is that you can mix a denser concentration of sucrose than with salt, as salt water becomes saturated at 25% which may be advantageous.
I have also been looking into using vibration to help break that tension, my first test was taking the rumble motor out of an xbox controller but it doesn't seem to have much effect. I am looking into ultrasonic vibration, but since ultrasonic is often used to emulsify liquids (which I definitely don't want) I'm hesitant to spend money on that equipment.
Thanks for your help, any direction you or anyone else can give me is greatly appreciated.