Conformations of end-labeled alkanes in a rigid polymer matrix
were investigated using the pulsed double
electron-electron resonance (DEER) method. To this end, dipolar
spectra of a series of aliphatic dicarbonic
acids with 8−20 methylene units and chain ends bifunctionalized with
nitroxide radicals were recorded in a
polystyrene matrix. The biradicals are derived from hindered amine
light stabilizers (HALS), used as polymer
additives. Analysis of the dipolar spectra allows the
determination of the end-to-end distances of the oligomer
biradicals. The experiments show that the “flexible” alkane
chains are almost completely stretched. This
observation is consistent with the results of force field
calculations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.