Characterizing the "shell phase" formed from amphiphilic picolinates.
The shell phase forms when certain picolinates are subjected to energy input (via sonication or vortexing) while exposed to a water/toluene mixture. A shell, about 600 A thick and containing the picolinate and (very likely) toluene, surround the water droplets that are always produced during the mixing process. Solubility in either phase appears to be deleterious to shell formation. The shells, stable for months, are not easily distorted but can be punctured, even skewered, with a syringe needle without destroying the sphere, yet there is enough mobility among the molecules to repair the physical damage after the needle is removed. This, plus the absence of evidence for crystallinity, suggests a solid or semisolid film forms when picolinates, with the aid of an aromatic solvent, are provided the energy to rearrange themselves on water droplet surfaces. Structure-activity comparisons among the 10 compounds studied indicate that chain-chain association and intermolecular hydrogen bonding are dominant forces in a side-by-side self-assembly of the molecules within the shells.
Menger
Fredric M
FM
Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA. menger@emory.edu
Galloway
Ashley L
AL
Lundberg
Dan
D
D000779:Anesthetics, Local / Q000494:pharmacology; D057927:Hydrophobic and Hydrophilic Interactions; D009682:Magnetic Resonance Spectroscopy; D018625:Microscopy, Atomic Force; D008956:Models, Chemical; D015394:Molecular Structure; D036103:Nanotechnology; D010848:Picolinic Acids / Q000138:chemical synthesis / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry
D000779:Anesthetics, Local; D010848:Picolinic Acids; D012997:Solvents; C030614:picolinic acid