The subsurface composition and properties might thereby allow the guests to partition off into one domain and then another guest partition into another domain.
"We have these channels to serve as capillaries to take in guest molecules and hold them inside the material,," said Wooley, a member of Washington University's Center for Materials Innovation, (CMI) which enables collaborators from across the Washington University campus to make basic and applied advances in materials research, touching many aspects of daily life..
She and her group received a research grant from Imperial Chemical Industries/National Starch to continue their study, with a goal of taking the guest molecules in and holding them. Using the technology of thermogravimetric analysis (TGA), Gerald O. Brown, Ph.D., a postdoctoral research associate in Wooley's group, began analyzing the release of these guests ?fragrance molecules ?as gaseous small molecules from the polymer across the network of the host material.
"We found that the temperatures at which the guests left the material were dependent on the composition of the host, and when the release of the small guest molecules was monitored from just an empty TGA pan, there was a slight difference versus those guests in the presence of either the hyperbranched fluoropolymer or the polyethylene glycol," she said. "There is a slight depression of temperature at which the small molecule fragrance volatilizes and becomes a gas."
However ,when they looked at the complex materials ?the ones designed to be anti-fouling materials -- they found a progression of decreasing temperature as they went with different amounts of poly(ethylene glycol) relative to hyperbranched fluoropolymer in the composite material.
"What's amazing is that there is a 55 degree temperature reduction at which this small molecule leaves the host material versus it leaving an empty pan,, she said. "Then we thought th
Source:Washington University in St. Louis