writer：Xinhui Zhong, Yi Liu, Huihuang Su, Guozhu Zhan, Yingfeng Yu*, Wenjun Gan
keywords：Phase separation, Viscoelasticity, Fillers
source：期刊
specific source：Soft Matter, 2011, 7, 3642-3650
Issue time：2011年
Here we report significant enhancement effect of mesoscopic fillers in viscoelastic phase separation of dynamic asymmetric polymer blends. Mesoscopic fillers with the size much larger than the dimension of polymer chains, from nanometer to micron, are preferentially immersed into the slow dynamic phase and phase interface due to the entanglement with polymer chains. For sufficiently high volume fraction and fine dispersion, mesoscopic fillers conduce to pronounced slowing down of the phase separation process, and result in refined structures with sharply decreased characteristic length scale. The pinning down of the phase separation is attributed to the dramatic increase of dynamic asymmetry from the entanglement of polymer chain with mesoscopic filler. The principal difference of mesoscopic fillers in classic and in viscoelastic phase separation is whether there exists filler enforced elastic-force balance condition. This suggests a general physical scenario of entanglement selection of the polymer chains under stress.