“…The resonance of N–H protons is known to shift dramatically depending on the nature of the hydrogen-bonding environment. ,,, Generally, a proton will become more deshielded and the resonance will shift downfield, as the hydrogen-bonding network becomes stronger. In the solid state, imidazole proton resonances appearing in the ∼9–12 ppm region are assigned to “mobile” protons in which the hydrogen-bonding network between N–H groups allows for rapid proton hopping. ,, Resonances in the region greater than ∼12 ppm are often assigned to “rigid” protons, where the hydrogen bonds between N–H groups are much stronger, and do now allow for fast proton dynamics. ,, In the spectra of the homopolymer (Figure a), two peaks from the imidazole N–H protons are indicative of a immobile, rigidly hydrogen-bonded population of protons at ∼14.0 ppm and a relatively weakly hydrogen-bonded or mobile population of protons at 11.4 ppm. As the temperature increases, the intensity of the 14.0 ppm peak (rigid, less mobile protons) decreases, while the intensity of the 11.4 ppm peak (mobile protons) increases (see Figure S4 for intensity plots).…”