Kwon Na Kyung, Kim Hyunhong, Han Im Kyung, Shin Tae Joo, Lee Hyun-Wook, Park Jongnam, Kim So Youn
ACS Macro Lett. 2018 Aug 21;7(8):962-967. doi: 10.1021/acsmacrolett.8b00475. Epub 2018 Jul 24.
While incorporation of nanoparticles in a polymer matrix generally enhances the physical properties, effective control of the nanoparticle/polymer interface is often challenging. Here, we report a dramatic enhancement of the mechanical properties of polymer nanocomposites (PNCs) using a simple physical grafting method. The PNC consists of low molecular weight poly(ethylene glycol) (PEG) and silica nanoparticles whose surfaces are modified with dopamine-modified PEG (DOPA-mPEG) brush polymers. With DOPA-mPEG grafting, the nanoparticle surface can be readily altered, and the shear modulus of the PNC is increased by a factor of 10 at an appropriate surface grafting density. The detailed microstructure and mechanical properties are examined with small-angle X-ray scattering (SAXS) and oscillatory rheometry experiments. The attractive interactions between particles induced by DOPA-mPEG grafting dramatically improve the mechanical properties of PNCs even in an unentangled polymer matrix, which shows a much higher shear modulus than that of a highly entangled polymer matrix.
虽然将纳米颗粒掺入聚合物基体中通常会增强物理性能，但有效控制纳米颗粒/聚合物界面往往具有挑战性。在此，我们报道了一种使用简单物理接枝方法显著增强聚合物纳米复合材料（PNC）机械性能的方法。该PNC由低分子量聚乙二醇（PEG）和二氧化硅纳米颗粒组成，其表面用多巴胺修饰的PEG（DOPA-mPEG）刷状聚合物进行了改性。通过DOPA-mPEG接枝，可以很容易地改变纳米颗粒表面，并且在适当的表面接枝密度下，PNC的剪切模量提高了10倍。通过小角X射线散射（SAXS）和振荡流变学实验研究了详细的微观结构和机械性能。DOPA-mPEG接枝诱导的颗粒间吸引力相互作用显著改善了PNC的机械性能，即使在未缠结的聚合物基体中也是如此，该基体显示出比高度缠结的聚合物基体更高的剪切模量。
