Ternary blends composed of a liquid crystalline polymer (LCP), nano-SiO2 and polysulfone (PSF) were prepared by melt blending. Very long and perfectly oriented LCP fibrils were in situ formed in capillary flows by adding 5 vol% of nano-SiO2 to binary PSF/LCP blend. Dynamic rheology analysis indicated that the sharp increase of elasticity was caused by higher content of nano-SiO2. Then the entrance angle was decreased and elongational stress increased when the polymer melt flowed through the abrupt contraction, which resulted in the fibrillation of LCP in PSF/LCP/nano-SiO2 system. (c) 2007 Elsevier Ltd. All rights reserved.