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Influence of the thin‐film thickness and crystallization temperature on the spherulitic structure of polymer thin films
Author(s) -
Liu Jieping,
Qiao Xiaoping,
He Shuangai,
Cao Qikun,
Wang Hui
Publication year - 2009
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.31163
Subject(s) - crystallization , materials science , thin film , morphology (biology) , optical microscope , diffusion , growth rate , composite material , spherulite (polymer physics) , polymer , discontinuity (linguistics) , chemical engineering , polymer chemistry , scanning electron microscope , nanotechnology , geology , thermodynamics , paleontology , mathematical analysis , physics , geometry , mathematics , engineering
The spherulitic structure and morphology of poly(3‐hydroxybutyrate) (PHB) thin films crystallized from the melt were observed with a polarizing optical microscope. Depending on the thickness of the PHB thin film and crystallization temperature, banded and nonbanded spherulites could form. Reducing the thin‐film thickness and crystallization temperature was favorable for the formation of the banded structure. The morphology transition from banded spherulites to nonbanded spherulites was related to the ratio of the crystallization rate to the diffusion rate. The formation mechanism of the banded structure was examined with the discontinuity growth theory. A depletion zone was considered to appear periodically at the crystal growth front because of the slow diffusion rate, and this may have resulted in the banded spherulites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010