Crystal melting and its kinetics on poly(ethylene oxide) by in situ atomic force microscopy

The process of melting in poly(ethylene oxide) (PEO) is followed in real-time at elevated temperatures by atomic force microscopy (AFM) using a simple hot stage apparatus. AFM imaging of the morphology above the onset of melting revealed the dynamics of a complex melting process. The observed melting behavior of PEO is associated with the existence of separate dominant and subsidiary morphological entities. The morphological observations revealed that the melting process is not explained by a mechanism of crystal reorganization (melting–recrystallization–remelting or crystal thickening. The kinetic data shows that the crystal dimensions decrease proportional to time indicating a nucleation controlled melting process. The crystals melt instantaneously on heating and reveal a spread in the rates of melting of the radial {120} faces. This variation in rate of retrogression of the crystals is assumed to be related to a lamellar thickness distribution of the melt grown crystals.

[1]  M. Miles,et al.  Direct Observation of Polyethylene Shish-Kebab Crystallization Using in-Situ Atomic Force Microscopy , 2001 .

[2]  B. Wunderlich,et al.  Melting of Poly(oxyethylene) Analyzed by Temperature-Modulated Calorimetry , 1997 .

[3]  King Lun Yeung,et al.  Direct Observation of Growth of Lamellae and Spherulites of a Semicrystalline Polymer by AFM , 2001 .

[4]  Wolfgang M. Heckl,et al.  Procedures in scanning probe microscopy , 1998 .

[5]  G. Vancso,et al.  Real-time crystallization study of poly(ϵ-caprolactone) by hot-stage atomic force microscopy , 2000 .

[6]  Stephen Z. D. Cheng,et al.  Spherulite formation in poly(ethylene oxide) mixtures , 1990 .

[7]  G. R. Brown,et al.  The (010)–(120) crystal growth face transformation in poly(ethylene oxide) spherulites , 1998 .

[8]  P. Barham,et al.  Direct observations of the growth of spherulites of poly(hydroxybutyrate-co-valerate) using atomic force microscopy , 1998 .

[9]  P. J. Phillips,et al.  Melting behavior of high-temperature polymers , 1996 .

[10]  H. D. Keith,et al.  A Phenomenological Theory of Spherulitic Crystallization , 1963 .

[11]  Gyula J. Vancso,et al.  Real-time imaging of melting and crystallization in poly(ethylene oxide) by atomic force microscopy , 1998 .

[12]  N. Hannay,et al.  Treatise on solid state chemistry , 1973 .

[13]  G. Vancso,et al.  Imaging of Melting and Crystallization of Poly(ethylene oxide) in Real-Time by Hot-Stage Atomic Force Microscopy , 1997 .

[14]  Y. Inoue,et al.  In situ observation of lamellar growth in thin films for poly[(R)-3-hydroxybutyric acid-co-6-hydroxyhexanoic acid] at a high crystallization temperature of 110°C by atomic force microscopy , 2001 .

[15]  C. Straupé,et al.  Isothermal growth, thickening and melting of poly(ethylene oxide) single crystals in the bulk. Part 4.—Dependence of pathological crystal habits on temperature and thermal history , 1979 .

[16]  John D. Hoffman,et al.  The Rate of Crystallization of Linear Polymers with Chain Folding , 1976 .

[17]  A. Vaughan,et al.  Crystallization and Morphology , 1996 .

[18]  E. Fischer.  Effect of annealing and temperature on the morphological structure of polymers , 1972 .

[19]  S. Magonov,et al.  Atomic Force Microscopy Visualization of Morphology and Nanostructure of an Ultrathin Layer of Polyethylene during Melting and Crystallization , 2000 .

[20]  R. H. Olley,et al.  On crystallization phenomena in PEEK , 1988 .

[21]  Igor Muševič,et al.  Temperature controlled microstage for an atomic force microscope , 1996 .