Isothermal growth, thickening, and melting of polyethylene oxide) single crystals in the bulk. II

Characteristic features of isothermal growth, thickening, and melting of melt‐grown single crystals of poly(ethylene oxide) fractions, as reported in a recent paper, are complemented and further discussed. A newly discovered phenomenon–isothermal superheating–is described and its implications are discussed. Growth and thickening rate data are analyzed in terms of the two independent molecular parameters which determine the lamellar thickness: the number, n, of folds per molecule and the total chain length, λ Current formulations of kinetic theories are critically analyzed in view of their applicability to the present growth rate data. The analysis reveals that, for the low‐molecular‐weight fractions, the theory only applies to fast growth obtained at high undercooling. At low undercooling, where molecules deposit in extended or n‐times folded‐chain conformation, however, growth proceeds by a nucleation mechanism which appears to be quite different from that implied by the theory.