A different type of additive could make facial tissues softer. Supercritical carbon dioxide appears to deposit additives in these materials better than liquid solvents such as water. Such liquid solvents don't let the polymer strings shrink back into their original shape. They can kink up the material and make it weak. A really good example of the effects of liquid solvent on a material is what happens when you get a piece of paper wet.
Water penetrates the fibers of the paper, so the paper swells a little bit.
And when the water evaporates out of the paper, it pulls those fibers and twists them, so the paper crinkles. Now Tomasko wants to find out how fast the process works. He and the other researchers are constructing a device that will contain the polymer at high pressure and time how long it takes for the supercritical carbon dioxide and additive to penetrate the material. Pam Frost is an associate editor with University Communications.