In-situ Observation of the Growth of Fibrous and Dendritic Crystals in Quasi-2-dimensional Poly(ethylene oxide) Ultrathin Films

Crystal growth processes of poly(ethylene ! oxide) were followed from the original nucleation sites by using atomic force microscopy. Two distinct quasi-2-dimensional crystals about 4 nm thick were obtained from as-spun polymer ultrathin films: fibrous crystals, generated by the shearing field via spin-coating, coexist with conventional dendrites. The growth of the two structures is dominated by diffusion limited aggregation, though the growth rate of the fibrous crystals is around one order of magnitude faster than that of the dendrites. The fibrous crystals are more stable than the dendritic ones.