Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, United States.
Nano Lett. 2011 May 11;11(5):1997-2003. doi: 10.1021/nl200366z. Epub 2011 Apr 12.
We describe an approach to prepare co-continuous microstructured blends of polymers and nanoparticles by formation of a percolating network of particles within one phase of a polymer mixture undergoing spinodal decomposition. Nanorods or nanospheres of CdSe were added to near-critical blends of polystyrene and poly(vinyl methyl ether) quenched to above their lower critical solution temperature. Beyond a critical loading of nanoparticles, phase separation is arrested due to the aggregation of particles into a network (or colloidal gel) within the poly(vinyl methyl ether) phase, yielding a co-continuous spinodal-like structure with a characteristic length scale of several micrometers. The critical concentration of nanorods to achieve kinetic arrest is found to be smaller than for nanospheres, which is in qualitative agreement with the expected dependence of the nanoparticle percolation threshold on aspect ratio. Compared to structural arrest by interfacial jamming, our approach avoids the necessity for neutral wetting of particles by the two phases, providing a general pathway to co-continuous micro- and nanoscopic structures.
我们描述了一种通过在经历旋节分解的聚合物混合物的一相中形成颗粒的渗透网络来制备聚合物和纳米颗粒的共连续微结构共混物的方法。将 CdSe 纳米棒或纳米球添加到聚苯乙烯和聚（甲基乙烯基醚）的近临界混合物中，该混合物被淬火到高于其下临界溶液温度。超过纳米颗粒的临界负载，由于颗粒在聚（甲基乙烯基醚）相中聚集形成网络（或胶体凝胶），相分离会被阻止，从而产生具有几微米特征长度尺度的共连续类似旋节的结构。发现实现动力学阻止的纳米棒的临界浓度小于纳米球，这与纳米颗粒渗透阈值对纵横比的预期依赖性定性一致。与通过界面阻塞的结构阻止相比，我们的方法避免了两相对颗粒的中性润湿的必要性，为共连续微观和纳米结构提供了一种通用途径。
