Molecular dynamics in solid polymers

Internal plasticization of chitosan with oligo(dl-lactic acid) branches

“…4 depicts the CPMAS and SPEMAS spectra of CG01 to CG06 samples going from the less to the more substituted materials. The progressive narrowing of the OLA signals is evident, suggesting an increase in the molecular dynamics of OLA units as a function of the concentration [33]. The decrease of resolution and intensity of all chitosan signals in the spectra of CG04, CG05 and CG06 samples suggests that, apart from the increase of conformational disorder, an increase in the molecular mobility of the chitosan chains takes place.…”

Effects of solvent concentration and composition on protein dynamics: 13 C MAS NMR studies of elastin in glycerol–water mixtures

“…13 C CP MAS NMR spectra provide valuable information about such fluctuations [35,47]. Specifically, when molecular dynamics is absent or slow, i.e., when the correlation time is longer than 10 −4 s, 13 C CP MAS NMR spectra feature well resolved lines.…”

“…On the one hand, 13 C NMR yields valuable insights into the protein dynamics. In particular, combination of the cross polarization (CP) and magic angle spinning (MAS) techniques enables spectral resolution of signals from structurally different carbons in the solid state, whereby the intensity and width of the various resonances yield information about molecular dynamics [35]. So far, 13 C CP MAS NMR line-shape analysis was used to show that elastin dynamics sets in above a hydration level of 0.2 g/g [36,37], consistent with the abovementioned dielectric studies [33].…”

Molecular relaxations in polyfluorene based cast films

“…To detect them we used the NMR method Centerband-Only Detection of Exchange (CODEX), which is capable of probing molecular motions with rates between 1 and 10 3 Hz [14,15]. The experiment detects the signal reduction due to changes in the orientation-dependent chemical-shift frequencies (encoded by a evolution period named Nt r ) that take place during a mixing time (t m ) [14].…”