Shanghai Key Laboratory of Advanced Polymeric Materials, State Key Laboratory of Bioreactor Engineering, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China.
Phys Chem Chem Phys. 2019 Jan 30;21(5):2651-2658. doi: 10.1039/c8cp06431h.
Janus nanoparticles (JPs), which are anisotropic nanoparticles with at least two opposite surface regions, have been demonstrated as highly efficient compatibilizers for polymer blends. However, there are still a number of open questions concerning the mechanism behind the influence of JPs on the phase separation dynamics of polymer blends. Herein, we report a counter-intuitive feature of JPs concerning their roles during spinodal decomposition (SD); that is, they promote the decomposition of unlike polymers in the early stage of SD but retard it during the late stage. This is in remarkable contrast to traditional compatibilizers such as block copolymers and homogenous nanoparticles, which impede phase separation during both stages. We further demonstrate that the unique promoting effect of JPs at early times is due to the formation of microphase-separated homopolymer-rich regions in the vicinity of opposite JP surface regions. Our findings are expected to have important implications for the phase separation behavior of JP-compatibilized polymer blends, whose morphologies and performance could be controlled by tuning the interactions between the constituent polymers and JP-based compatibilizers.
Janus 纳米粒子（JPs）是具有至少两个相对表面区域的各向异性纳米粒子，已被证明是聚合物共混物的高效增容剂。然而，关于 JPs 对聚合物共混物相分离动力学影响的机制仍存在许多悬而未决的问题。在此，我们报告了 JPs 在旋节分解（SD）过程中作用的一个反直觉特征；也就是说，它们在 SD 的早期促进了不同聚合物的分解，但在后期却减缓了分解。这与传统的增容剂（如嵌段共聚物和均一纳米粒子）形成鲜明对比，后者在两个阶段都会阻碍相分离。我们进一步证明，JPs 在早期的独特促进作用是由于在相反 JP 表面区域附近形成了富均相分离的聚合物微区。我们的研究结果有望对 JP 增容聚合物共混物的相分离行为产生重要影响，通过调整组成聚合物与基于 JP 的增容剂之间的相互作用，可以控制其形态和性能。
