Abstract
The crystalline morphology and structure of poly(L-lactide) (PLLA) in a PLLA film-chloroform system were investigated by means of wide angle X-ray diffraction (WAXD), polarized optical microscopy (POM) and atomic force microscopy (AFM). Birefringent and nonbirefringent ring banded supra-structures with radial periodic variation of thickness were obtained, which were induced by micro-evaporation of solvents and concentration gradient of PLLA. The ring banded morphologies consisted of multilayer lamellar crystals, which is a manifestation of alternating ridge and valley bands of periodic variation of thicknesses along the radial direction. The formation of the ring banded supra-structures is associated with diffusion and crystal growth induced periodic variation of concentration gradient, which is attributed to diffusion-related rhythmic growth and the competition between diffusion of polymer segments and growth of crystal lamellae. The mechanism of such banded-ring formation was explored on the basis of rhythmic growth resulting from non-linear diffusion
Original language | English |
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Journal | CrystEngComm |
Volume | 16 |
Issue number | 1 |
Pages (from-to) | 94-101 |
Number of pages | 8 |
ISSN | 1466-8033 |
DOIs | |
Publication status | Published - 2014 |
Keywords
- PHERULITIC GROWTH-RATES; THIN-FILMS; DIBLOCK COPOLYMERS; RHYTHMIC GROWTH; POLY(EPSILON-CAPROLACTONE) SOLUTION; SEMICRYSTALLINE POLYMER; ISOTACTIC POLYSTYRENE; MISCIBLE MIXTURES; CRYSTAL-STRUCTURE; MELTING BEHAVIOR