Separated Systems with Covalently Bound Proton Solvents

Separated Systems with Covalently Bound Proton Solvents 

Both types of heterogeneous systems discussed above comprise a polymeric domain and a low molecular weight liquid-like domain containing the proton sol- 

The type of bonding appears to be more important, that is only single bonds allow rapid reorientation of the bonded proton solvent, which is a persistent element in the proton conduction mechanism. But even for single bonds, significant barriers appear for the rotation of the proton solvent around this bond of the isolated (non-hydrogen bonded) alkane segment, with higher barriers for the phosphonic acid ( 0.10 eV) compared to heterocycles ( 0.04 eV) [101]. 

Recently, fully polymeric systems with side chain architectures have been developed that still exhibit high proton mobility despite complete long-range immobUi- 

This is directly evidenced by the echo attenuation of the proton resonance in PFG-NMR experiments of phosphonic acid functionalized oligomer [104], Only the echo of the phosphonic protons is attenuated ivhile the echo of the oligomer protons is only slightly affected by the magnetic field gradient (Fig. 23.9). The reader may recall that complexation of phosphoric acid and a basic polymer does not show any sign of this effect (see Fig. 23.7), which opens the way to the development of true single ion conductors. 

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