We present a proton fast field-cycling (FFC) NMR relaxometry study of the molecular dynamics in three different deuterated water-dispersed triblock copolymers of ethylene oxide (EO) and propylene oxide (PO):EO₈₀PO₂₇EO₈₀(F68), EO₁₄₁PO₄₄EO₁₄₁ (F108), and EO₁₀₁PO₅₆EO₁₀₁(F127). Independently of the phase and molecular arrangement, bi-exponential decays of the magnetization during the spin-lattice relaxation process could be observed for F127, while mono-exponential decays were measured for F68 and F108. This fact has been attributed to the relative ratio of PEO and PPO protons for each case. In F127, each component of the magnetization decay could be associated with a particular block of the co-polymer. A direct consequence of this fact is the independent characterization of the molecular dynamics of each block. It was found that the dominant relaxation mechanism can be attributed to the Rouse model, and it seems to be independent on whether the molecules are incorporated into a micelle, or as individual unimers in the aqueous solution. The experimental results and the provided explanation are consistent with entanglement-free self-assembled structures, and a fast exchange of unimers between the micellar structure and the solvent. This particular feature was also investigated in F68 and F108, although for these cases a mono-exponential decay of the magnetization was observed. NMR relaxometry results are complemented with other relaxation experiments in the rotating frame, NMR spectroscopy and atomic-force microscopy.

我们提供了一种质子快速场循环（FFC）NMR弛豫研究，研究了环氧乙烷（EO）和环氧丙烷（PO）的三种不同的氘化水分散三嵌段共聚物的分子动力学：EO ₈₀ PO ₂₇ EO ₈₀（F68）， EO ₁₄₁ PO ₄₄ EO ₁₄₁（F108）和EO ₁₀₁ PO ₅₆ EO ₁₀₁（F127）。与相和分子排列无关，对于F127可以观察到自旋晶格弛豫过程中磁化强度的双指数衰减，而对于F68和F108则可以观察到单指数衰减。这一事实归因于每种情况下PEO和PPO质子的相对比例。在F127中，磁化强度衰减的每个成分都可能与共聚物的特定嵌段相关。这一事实的直接后果是每个嵌段分子动力学的独立表征。已经发现，主要的弛豫机制可以归因于Rouse模型，并且似乎与分子是否结合到胶束中或作为水溶液中的单独单体无关。实验结果和所提供的解释与无缠结的自组装结构以及胶束结构与溶剂之间的单体快速交换相一致。尽管在这些情况下，观察到磁化强度呈单指数衰减，但在F68和F108中也研究了此特殊功能。NMR弛豫测定结果与旋转框中的其他弛豫实验，NMR光谱学和原子力显微镜相辅相成。