¹H and ¹³C relaxation for the resolved crystalline and amorphous phases of polyethylene oxide

Polymer electrolyte poly(ethylene oxide)/LiCF3SO3 studied by solid-state13C NMR spectroscopy andab initio calculations

“…The same spectrum was also obtained under the same conditions, but with first 16 dummy scans. In these spectra the signal of crystalline PEO segments with long T 1 is suppressed and predominantly amorphous PEO segments (with much shorter T 1 values 15,16) ) are detected 21,22) . Spectra measured during T 1 measurements show that the spin-lattice relaxation of LiCF 3 SO 3 carbons is rather fast (T 1 f 1 s).…”

“…6. Similarly to neat PEO or complexes of PEO with benzene derivatives 15,16,20) , the T 1 relaxation of amorphous PEO carbons is rather fast (T 1 a 1 s, cf. the first experimental points with the shortest time delays in Fig.…”

“…This value is significantly larger than the energy of 7.1 kcal/mol obtained in a similar way for the diethyl ether/p-nitrophenol (PNP) interaction (taking into account various hydroxybenzenes, strongest hydrogen bonds were found in the PEO/PNP complex by infrared spectra 20) ), in agreement with 13 C NMR results. [15][16][17] . This result shows that coordination to a Li + cation is sufficient to explain the observed "upfield" shift of the PEO resonance in 13 C NMR spectra.…”

“…5 and 6 in ref. 15) ) and centered at d = 72 ppm [15][16][17] . The detection of the signal of the crystalline phase in neat PEO requires a very short contact time (L 0.1 ms).…”

Studies on the crystalline intercalate formed by poly(ethylene oxide) and two different kinds of guest molecules

“…Several authors have reported that the 13 C NMR line attributed to the crystalline phase in pure PEO is very broad (line width > 1KHz) and centered at 72 ppm [14][15][16]. The unusual broadness of this line was considered to originate from the competition between molecular motion and decoupling [14,17,18].…”