Crystallization and morphology of ultrathin films of poly(d-lactide) with BAB block copolymers in which the A block is made of poly(l-lactide)

When poly(d-lactide) (PDLA) is mixed with poly(l-lactide) (PLLA) of similar molecular weight and crystallized from the melt in ultrathin films (30 nm), hexagonal single crystals are obtained at the equimolar composition, and triangular single crystals at non-equimolar compositions. Here, stereocompl...

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Bibliographic Details
Published in:Polymer (Guilford) 2017-05, Vol.117, p.25-29
Main Authors: Tien, Nguyen-Dung, Prud'homme, Robert E.
Format: Article
Language:English
Subjects:
Atomic force microscopy
Block copolymers
Copolymer
Copolymers
Crystallization
Crystals
Microscopy
Molecular weight
Morphology
Poly(L-lactide)
Polylactic acid
Polylactide
Single crystals
Stereocomplexation
Stereocomplexes
Studies
Thin films
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Summary:When poly(d-lactide) (PDLA) is mixed with poly(l-lactide) (PLLA) of similar molecular weight and crystallized from the melt in ultrathin films (30 nm), hexagonal single crystals are obtained at the equimolar composition, and triangular single crystals at non-equimolar compositions. Here, stereocomplexes are formed by blending PDLA with a PLLA incorporated as the central block of a triblock copolymer made with poly(2-dimethylaminoethyl methacrylate) (PDMAEMA-b-PLLA-b-PDMAEMA or BAB); the resulting single crystals are studied by in-situ atomic force microscopy. The imbalance between the PDLA and PLLA characteristics, due to the presence of the B blocks of the triblock copolymer, leads to triangular single crystals at equimolar compositions, the hexagonal single crystal morphology being shifted to off-equimolar compositions. The importance of the shift depends upon the A/B ratio and the molecular weight of each species. [Display omitted] •Stereocomplexes of PDLA and PDMAEMA-b-PLLA-b-PDMAEMA were successfully observed in ultrathin films (30 nm).•The single crystals are hexagonal or triangular depending on the PLLA/PDLA ratio and molecular weight of each species.•The shift in morphology depends upon the mobility of two species.
ISSN:0032-3861
1873-2291
DOI:10.1016/j.polymer.2017.03.058