Polymer segmental dynamics in polymer nanocomposites (PNCs) can be significantly perturbed from bulk and underlie macroscopic mechanical and transport properties, but fundamental studies are necessary to build correlations between dynamics and properties. To elucidate a mechanistic description of this perturbation and isolate different molecular motions, we present quasi‐elastic neutron scattering (QENS) measurements on PNCs with attractive interactions comprised of colloidal silica nanoparticles (NPs) uniformly dispersed in poly(2‐vinyl pyridine) (P2VP) with and without backbone deuteration. Measurements of fully‐protonated P2VP probe the dynamics of both the polymer backbone and pyridine pendant group; whereas measurements of backbone‐deuterated P2VP isolate the dynamics of only the pyridine ring. On the small length scales (~1 nm) and fast time scales (~1 ns) captured by QENS, we show that the backbone and pyridine ring dynamics are highly coupled at high temperatures and both are slowed by about 35% relative to neat polymer in 25 vol% PNCs. This observation implies that the backbone and pendant interfacial dynamics are perturbed similarly in PNCs, which further develops our fundamental understanding of microscopic properties in PNCs.

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聚（2-乙烯基吡啶）/二氧化硅聚合物纳米复合材料中骨架与吡啶动力学之间的相关性

聚合物纳米复合材料（PNC）中的聚合物链段动力学可能会从体积上明显受到干扰，并成为宏观力学和传输性能的基础，但是建立动力学与性能之间的相关性必须进行基础研究。为了阐明这种扰动的机理描述并分离出不同的分子运动，我们对PNC进行了准弹性中子散射（QENS）测量，该过程具有有吸引力的相互作用，该相互作用包括均匀分散在聚（2-乙烯基吡啶）（P2VP）中的胶体二氧化硅纳米颗粒（NP） ），有或没有骨干氘代。全质子化的P2VP的测量探测了聚合物主链和吡啶侧基的动力学；而主链氘代P2VP的测量仅分离了吡啶环的动力学。在QENS捕获的小长度标度（〜1 nm）和快速时间标度（〜1 ns）上，我们显示了骨架和吡啶环动力学在高温下高度耦合，并且相对于纯净聚合物，两者都降低了约35％在25％（体积）PNC中。该观察结果表明，PNC中的骨架和悬垂界面动力学受到类似的扰动，这进一步发展了我们对PNC中微观性质的基本理解。