Abstract The interphase between nanofillers and rubber matrix, also known as “bound rubber (BR)” composed of a tightly BR (TBR) layer that strongly interacts with the filler and a loosely BR (LBR) layer that is physically adsorbed, plays an important role in the properties of rubber nanocomposites. Up to now, there is seldom direct evidence of such interfacial double layer structure and their thickness. In this study, we quantitatively identified the interphase of a representative nano silicon dioxide (SiO2)/rubber composites by using peak force quantitative nanomechanical mapping (PFQNM) mode of Atomic Force Microscope (AFM). The thickness of interphase was quantitatively obtained, and the double layer structure of interphase was directly identified based on PFQNM images and the corresponding force-distance curves, and was further evidenced by high resolution transmission electron microscopy. We further studied the effect of molecular polarity on interphase of SiO2/hydrogenated nitrile butadiene rubber (HNBR) composites. Interestingly, the molecular polarity of HNBR has almost no effect on the thickness of TBR layer but has a significant effect on the LBR layer, leading to the remarkable increase in the total interfacial thickness of the composites with increasing the acrylonitrile content. The mechanism for the formation of interfacial double layer structure of BR and the effect of molecular polarity on the double layer structure was discussed. This study provides a simple method to identify and deeply understand the double layer structure of the interphase, and thus provides guidance for the design of interphase for the preparation of high performance rubber nanocomposites.

中文翻译：

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利用原子力显微镜的纳米力学映射技术定量识别和理解 SiO2/橡胶纳米复合材料的界面

摘要 纳米填料和橡胶基质之间的界面，也称为“结合橡胶 (BR)”，由与填料强烈相互作用的紧密 BR (TBR) 层和物理吸附的松散 BR (LBR) 层组成，起着重要的作用。对橡胶纳米复合材料性能的影响。到目前为止，很少有直接证据表明这种界面双层结构及其厚度。在这项研究中，我们通过使用原子力显微镜 (AFM) 的峰值力定量纳米力学映射 (PFQNM) 模式定量鉴定了具有代表性的纳米二氧化硅 (SiO2)/橡胶复合材料的界面。定量获得界面层厚度，并根据PFQNM图像和相应的力-距离曲线直接识别界面层的双层结构，高分辨率透射电子显微镜进一步证明了这一点。我们进一步研究了分子极性对 SiO2/氢化丁腈橡胶 (HNBR) 复合材料界面的影响。有趣的是，HNBR 的分子极性对 TBR 层的厚度几乎没有影响，但对 LBR 层有显着影响，导致复合材料的总界面厚度随着丙烯腈含量的增加而显着增加。讨论了BR界面双层结构的形成机理以及分子极性对双层结构的影响。本研究为识别和深入了解界面的双层结构提供了一种简单的方法，