Isothermal growth, thickening and melting of poly(ethylene-oxide) single crystals in the bulk

Structure of Polymer Single Crystals

“…3-22) make it possible to follow morphological changes associated with changes in n, and the crystallographic pathway of chain unfolding (in the present case from n = 1 to full chain extension) within the lamellae. Isothermal melting of such crystals was shown to take place by lateral contraction of the crystals, which is at variance with an earlier model of melting from the fold surface inwards (Kovacs and Straupe, 1980). Parallel work using similar techniques helped establish that integral folding, which implies that the chain ends are essentially located at the fold surface, is not linked with the chemical nature of these chain ends, since ethyl terminated (instead of OH) PEOs also display the same behavior.…”

“…The most classical and thoroughly investigated defect of this class is the so-called kink, which, in a chain based on all trans conformation (Pechhold, 1968 Kovacs and Straupe, 1980). Scale bar: 5 um.…”

Branched Crystalline Patterns Formed Around Poly(ethylene oxide) Dots in Humidity

“…The length of fully extended crystalline molecules for PEO 6k and PEO nm. [22] The 8-10 nm thick lamellae in PEO 6k samples imply that the PEO chains in the lamellae in fractal-like parts fold 3 or 4 times. However, in the case of PEO 2k samples, the 10-12 nm thickness of the lamellae in fractal-like parts compares well to the length of fully extended crystalline PEO 2k chains.…”

Model experiments for a molecular understanding of polymer crystallization

“…PEO is a well investigated polymer. 25,26,28,29 Molecular details of all investigated polymers are given in Table 1. For most of our crystallization experiments, we used polymer monolayers.…”

“…[21][22][23][24][25][26] However, the corresponding relaxations processes in the crystalline state are usually slow and rather localized because the long sequence of connected segments is not very mobile. The morphology of a polymer crystal does not only depend on the rate at which it was created (i.e., the crystallization temperature) but also, and sometimes most importantly, on the thermal treatment (e.g., the storage conditions) the sample experienced after the initial crystallization process.…”