What is so special about the sorption behavior of highly fluorinated compounds?

Highly fluorinated organic compounds are often said to exhibit unique sorption and partition properties. Terms such as "fluorophilicity" have been used to describe these properties, and fudge factors depending on the degree of fluorination have been used in predictive partition models to make them work for fluorinated solutes. Here we demonstrate that highly fluorinated compounds differ from other molecules only in that they exhibit van der Waals interactions much smaller than those of other molecules of same size. A simple cavity model for partitioning is shown to give good results for fluorinated compounds if the nonspecific interactions are correctly parametrized.