Microenvironmental and conformational structure of triblock copolymers in aqueous solution by 1H and 13C NMR spectroscopy

Induced micellization and micellar transitions in aqueous solutions of non-linear block copolymer Tetronic® T904

“…4. The copolymer species dissolved in D 2 O gives rise to three resolved signal regions that were assigned according to previously published NMR results on the linear PEO-PPO-PEO block copolymers [44][45][46]. Specifically, the triplet at 1.16 ppm is attributed to the protons of the PPO -CH 3 groups.…”

Micellization in aqueous solution of an ethylene oxide–propylene oxide triblock copolymer, investigated with 1H NMR spectroscopy, pulsed-field gradient NMR, and NMR relaxation

“…1a. According to the previous assignments [31], the resonance signal seen as a triplet at ∼1.16 ppm is the PO -CH 3 protons, the broad peaks between 3.45 and 3.65 ppm are attributed to the PO -CH 2 -units, the sharp peak at ∼3.7 ppm is the protons of the PEO -CH 2 -units, and the remaining sharp peak at ∼5.0 ppm is the signal of residual HDO.…”

“…1b. At lower temperatures, the PO -CH 3 signal splits into a triplet due to the combination of the indirect J coupling between the PO -CH 3 and the PO -CH-protons through chemical bonds [29] and the direct coupling between the PO -CH 3 and the -CH 2 -protons through space [31]. The disappearance of the triplet of the PO -CH 3 signal with increasing temperature indicates that a change of chemical environment and/or the orientation of the PO -CH 3 groups may occur during the micellization process.…”

Mechanism of PEO–PPO–PEO micellization in aqueous solutions studied by two-dimensional correlation FTIR spectroscopy

“…The conformational changes of EO segments of PEO-PPO-PEO block copolymers during micellization were validated by FTIR, FT-Raman and NMR studies [14,[32][33][34]. The 2D spectra of Pluronics give further information about the sequence of the two types of conformations: nonpolar conformation changed before polar conformation of EO segments during the heating process.…”