Abstract
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.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have