In this study, we investigate interfacial phenomena in nanocomposites of the ‘core-shell’ type based on fumed silica nanoparticles (core) and linear polydimethylsiloxane, PDMS, (shell) of low molecular weight (~3 kg/mol). In particular, we study the interfacial polymer in terms of the amount and dynamics and compare between two methods of nanocomposite preparation, the simple impregnation (liquid phase method) and the relatively new and environmentally more friendly mechano-sorption modification, MSM (gas phase method). To that aim, we employ differential scanning calorimetry, DSC, and broadband dielectric spectroscopy, BDS, as the main investigation tools, supplemented by scanning electron microscopy, SEM, and Fourier transform infrared spectroscopy, FTIR. The silica-PDMS interactions result in constraints on the polymer diffusion/mobility and, subsequently, on the formation of an interfacial polymer fraction being rigid in DSC or exhibiting retarded dynamics in BDS. In qualitative agreement between the two techniques, the amount of interfacial polymer was found systematically larger for MSM as compared to impregnation, confirming actually the scope of employing MSM. The latter is shown here for the first time in silica nanocomposites employing the said experimental methodology. From the basic research point of view, the bulk-like dynamics (glass transition and α/α_c relaxations) is mainly similar between the nanocomposites and neat PDMS, with the larger interfacial amounts imposing a slight increase of the T_g. Owing to the high resolving power of BDS, the interfacial polymer dynamics is recorded individually via the α_int relaxation next to the bulk-like α/α_c in the nanocomposites. α_int exhibits a non-cooperative character and relatively high strength, which, comparing to previous work on similar and systems, suggests the existence of many PDMS tails distributed on the silica surfaces, with the interfacial chains packing being possibly more dense in the case of MSM as compared to impregnation.

在这项研究中，我们研究了基于气相二氧化硅纳米颗粒（核）和低分子量（〜3 kg / mol）的线性聚二甲基硅氧烷PDMS（壳）的“核-壳”型纳米复合材料的界面现象。特别是，我们从数量和动力学方面研究了界面聚合物，并比较了两种纳米复合材料制备方法，即简单浸渍（液相法）和相对较新且对环境更友好的机械吸附改性MSM（气相法）。 ）。为此，我们采用差示扫描量热法DSC和宽带介电谱BDS作为主要研究工具，并辅以扫描电子显微镜SEM和傅立叶变换红外光谱FTIR。二氧化硅-PDMS相互作用会限制聚合物的扩散/迁移率，并且 随后，在形成界面聚合物部分时，该界面聚合物部分在DSC中是刚性的，或者在BDS中表现出延迟的动力学。在两种技术之间的定性一致性方面，与浸渍法相比，系统地发现MSM界面聚合物的量更大，这实际上证实了MSM的应用范围。使用所述实验方法在二氧化硅纳米复合材料中首次显示了后者。从基础研究的角度来看，块状动力学（玻璃化转变和 使用所述实验方法在二氧化硅纳米复合材料中首次显示了后者。从基础研究的角度来看，块状动力学（玻璃化转变和 使用所述实验方法在二氧化硅纳米复合材料中首次显示了后者。从基础研究的角度来看，块状动力学（玻璃化转变和α / α _Ç松弛）主要是类似的纳米复合材料和纯的PDMS之间，具有较大的界面量施加的轻微增加Ť_克。由于高的分辨BDS的功率，界面聚合物动力学经由单独记录α _INT松弛的块状旁边α / α _ç在纳米复合材料。α _INT 表现出非合作的特性和相对较高的强度，与以前类似系统上的工作相比，这表明存在许多分布在二氧化硅表面的PDMS尾部，对于MSM，界面链堆积可能更致密。相比浸渍。