C-60-C-70 two-component fullerene nanowhiskers (C-60-C(70)NWs) were synthesized by liquid-liquid interfacial precipitation (LLIP) using various ratios of C-70 to C-60 and then analyzed using a focused ion beam processing apparatus (FIB-SEM), scanning electron microscopy (SEM). Raman spectroscopy, ultraviolet-visible (UV-vis) spectroscopy, X-ray diffraction (XRD) and high-performance liquid chromatography (HPLC). Both C-60 and C-70 were saturated in the supernatant solutions with fullerene compositions in the mother solutions ranging from 124 mass% C-70 to 73.4 mass% C-70. C-60-C(70)NWs contained a small amount of rhombohedral phase, indicating polymerization of C-60. The solid solubility limit of C-70 in the C-60 matrix was found to be 13.7 mass%. In addition to fine C-60-C(70)NWs, thick C-60-C-70 needle-like crystals were formed. The thick C-60-C-70 needle-like crystals were fractured using a molybdenum probe in the FIB. The fractured surfaces of the C-60-C-70 needle-like crystals showed modulated structures with chemical compositions characteristic of spinodal decomposition. The activation energy of diffusion was determined to be 37.1 kJ/mol. (C) 2014 Elsevier B.V. All rights reserved.