The AFM-tip-induced crystallization of poly(ethylene oxide)(PEO)melt droplets was studied．The melt droplets with the heght of 50～100 nm and the lateral size of 2～3 μm were obtained by melting the PEO ultrathin film on the mica surface．Forthe PEO samples with the number average molecular weights(Mn)ranged from 1．0×10 3 to 1．0×104g／mol

the lateral perturbation from the AFM tip with hard-tapping or nanoscratch mode could not induce the growth of the flat—on lamellae． By contrast

under AFM nanoindentation mode

the tip—induced crystallization occufred when a sufficiently high vertical tip force was applied to the melt droplets of PEO with Mn≥1．0×lO4g／mol．Moreover

the experimental results indicated that AFM-tip—induced crystallization with nanoindentation method had PEO molecular weight(viscosity)dependence．