TY - JOUR
T1 - Periodic crystal assembly of Poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid)
T2 - From surface to interior microstructure
AU - Wu, Chun Ning
AU - Woo, Eamor M.
AU - Nagarajan, Selvaraj
N1 - Funding Information:
This work has been financially supported by basic research grants ( MOST 108-2221-E-006-055 ) from Taiwan'sMinistry of Science and Technology(MOST (MOST) , to which the authors express their gratitude. S. Nagarajan is grateful to MOST Postdoc Research Fellowship from Taiwan government.
Publisher Copyright:
© 2021
PY - 2021/7/16
Y1 - 2021/7/16
N2 - Poly(3-hydroxybutyric acid-co-3-hydroxyl-valeric acid) (PHBV) crystallized in the presence of a polymeric diluent impurity is analyzed at specific crystallization temperatures (Tc) from 60 °C to 80 °C. 3D-dissected interior analysis for ring-banded spherulites evidently reveals that the alternate bands exist in not only top surface but also 3D interiors composted of grating-assembled lamellae. Aggregation of the lamellae, initially from two ends of nucleus sheaf-bundles, packs via crystal-by-crystal mode into either Archimedean single-spirals or Fermat's double-spirals, which constitute the “ridge” bands. Then from the ridge-band lamellae, secondary lamellae then branch out at 60–80° oblique angles, with irregular bending, twisting, or scrolling to accommodate in the confined space, to form the “valley” bands. Each new growth cycle repeats the fractal patterns of previous one. The periodic cycles repeat themselves in a fractal fashion to form a cross-lamellar structure, with “crossbar pitch” equal to its optical band spacing. Periodicity of aggregation in top surface and interior is depicted in detailed 3D assembly, beyond and distinguished from conventional planar analytical approaches, for novel mechanisms.
AB - Poly(3-hydroxybutyric acid-co-3-hydroxyl-valeric acid) (PHBV) crystallized in the presence of a polymeric diluent impurity is analyzed at specific crystallization temperatures (Tc) from 60 °C to 80 °C. 3D-dissected interior analysis for ring-banded spherulites evidently reveals that the alternate bands exist in not only top surface but also 3D interiors composted of grating-assembled lamellae. Aggregation of the lamellae, initially from two ends of nucleus sheaf-bundles, packs via crystal-by-crystal mode into either Archimedean single-spirals or Fermat's double-spirals, which constitute the “ridge” bands. Then from the ridge-band lamellae, secondary lamellae then branch out at 60–80° oblique angles, with irregular bending, twisting, or scrolling to accommodate in the confined space, to form the “valley” bands. Each new growth cycle repeats the fractal patterns of previous one. The periodic cycles repeat themselves in a fractal fashion to form a cross-lamellar structure, with “crossbar pitch” equal to its optical band spacing. Periodicity of aggregation in top surface and interior is depicted in detailed 3D assembly, beyond and distinguished from conventional planar analytical approaches, for novel mechanisms.
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U2 - 10.1016/j.polymer.2021.123866
DO - 10.1016/j.polymer.2021.123866
M3 - Article
AN - SCOPUS:85107147501
SN - 0032-3861
VL - 228
JO - Polymer
JF - Polymer
M1 - 123866
ER -