Time-resolved neutron scattering
data for poly(e-caprolactone)
during cooling from the melt. The
observed structural variations are
linked to the three key length scales
View full-size image
Many technologically important polymers are partially crystalline and their crystalline structure and morphology are critical to delivering the required properties.
Although the process whereby polymers crystallise by folding into thin lamellae was discovered some fifty years ago, the existence of a transition in which a randomly coiled polymer chain in the melt reorganises to form a chain-folded lamellar phase remains a subject of much debate and conjecture. Crystallisation involves conformational changes to produce chain segments with a regular conformation leading to a translationally ordered crystal containing chain-folded surfaces. Three key length scales characterise this process: chain-folded lamellae of thickness ~ 10nm, the crystal unit cell (~ 1nm), and chain-conformation details ( ~ 0.1nm). We have used Nimrod to follow, in real time, all three length scales during the crystallisation process. These experimental results are being used to develop detailed multiscale models of polymer crystallisation.
GR Mitchell, D Lopez Garcia, FJ Davis (Reading University), and DT Bowron (ISIS)
Research date: January 2010
Contact: Prof GR Mitchell, email@example.com
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