Sluggish growth of poly(ε-caprolactone) leads to petal-shaped aggregates packed with thick-stack lamellar bundles

Kinetically sluggish growth of poly(epsilon-caprolactone) at high T-c = 50 degrees C leads to a peculiar banding morphology, where thick-stacked lamellae self-assemble into camellia-petal-like bands with their outer rims divided into a ca. 10 lobs of round-shaped petals. The sluggish growth at T-c = 50 degrees C thick films is inductive and the thickened lamellae self-assemble into aggregates of peculiar and novel camellia-petal-shaped ring bands. Using novel morphology analyses via 3D-dissection approaches, the lamellae underneath the ridge bands are shown to be all perpendicular to the substrate plane, i.e. normally-oriented with respect to the substrate surface; whereas, the interior lamellae underneath the valley band are all flat-on and horizontal to the substrate plane. Stereo-depiction clearly demonstrates that the interior lamellae are periodically grating architectures with a fixed crossbar pitch of 20-30 mu m of the interior lamellar assembly, matching with the optical inter-ring spacing of optical bands. The mechanisms of growth and assembly are probed in detail.

Automated summary

At 50 degrees Celsius, poly(epsilon-caprolactone) exhibits kinetically sluggish growth, resulting in a unique camellia-petal-like morphology with a periodic interior structure. Three-dimensional dissection analyses reveal perpendicular lamellae underneath the ridge bands and flat-on lamellae underneath the valley bands on the substrate plane.