W Tungsten

To unravel the exact composition and structure of aggregates in an aqueous solution of 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF₄]), we performed static and dynamic light-scattering measurements, as well as transmission electron microscopy (TEM). Results from this work show that the aggregates are vesicles and unstable; herein, we discuss the driving force behind the self-assembly. Apart from the van der Waals forces and repulsive electrostatic interactions between adjacent cation clusters, the hydrogen-bonding forces as well as counterion effects might also contribute to this driving force. The information obtained here is useful for a better understanding of the vital role that aggregation behavior plays in the field of ionic liquid recovery, and its potential use in controlled release, drug delivery, and petroleum recovery.

Deviant behavior: The structure of aggregates in an aqueous solution of [Bmim][BF₄] were examined and revealed to be vesicles (see graphic, white circles are H₂O) and unstable. This ultimately led to the conclusion that their aggregation behavior in water is somewhat different from that of surfactants, although both are surface-active agents.