Electron spin resonance magnetic polymers

The charged quasiparticles can be probed by electrical dc conductivity measurements (for polarons), magnetic susceptibility (for polarons and bipolarons), electron-spin resonance (ESR) (for polarons) and optical measurements (for polarons and bipolarons). As ESR is well suited for studying spin-carrying polarons, optical modification of the ESR (optically detected magnetic resonance ODMR) can be applied to link the emissive or absorbing properties of the polymer with its spin state. 

Electron spin resonance spectroscopy (ESR), also known as electron paramagnetic resonance (EPR), is based on the property that an unpaired electron placed in a magnetic field shows a typical resonance energy absorption spectrum sensitive to its environment. Recently, this technique, which was primarily developed for biological studies of membrane properties, has been adapted for the study of adsorbed polymer/surfactant layers. The mobility of the ESR probe (stable free radical incorporated into the polymer or surfactant molecule) depends of orientation of the surfactant or polymer and the viscosity of the local environment around the probe. 

Scientists have used a wide arsenal of analytical techniques to monitor chemical and physical transformations of polymers following exposure to laser radiation, among which UV-Vis absorption, nuclear magnetic resonance (NMR) spectroscopy, electron spin resonance (ESR) spectroscopy for detection of free radicals, GC/MS analysis, FTIR for detection of various functional groups and bonds, X-ray photoelectron spectroscopy (XPS) for the chemical composition of surfaces, optical, and fluorescence microscopy, atomic force microscopy (AFM) for surface topography, quartz crystal microbalance (QCM) for in situ mass loss measurements, and so forth. 

Characterization of the chemical structure of highly cross-linked polymers, and of the chemical changes that accompany degradation processes, relies on spectroscopic methods. Solid-state nuclear magnetic resonance techniques have the potential to allow a more detailed characterization than before possible of the chemical environment and structure of chemical crosslinks in elastomers and thermoset epoxies. Degradation processes in cross-linked systems have been studied by using infrared spectroscopy, solid-state NMR, and electron spin resonance. 

The measuring of radio-frequency-induced transmissions between magnetic energy levels of atomic nuclei. It is a powerful method for elucidating chemical structures, such as by characterizing material by the number, nature, and environment of the hydrogen atoms present in a molecule. This technique is used to solve problems of crystallinity, polymer configuration, and chain structure. See chemistry, analytical electron spin resonance spectroscopy thermal analysis. 

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