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Stereocontrolled Entanglement‐Directed Self‐Alignment of Poly(lactic acid) Cylindrites
Author(s) -
Xu Huan,
Hua Geng,
Odelius Karin,
Hakkarainen Minna
Publication year - 2016
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201600364
Subject(s) - superstructure , crystallization , lactic acid , morphology (biology) , quantum entanglement , isothermal process , polymer , materials science , relaxation (psychology) , polymer chemistry , chemical engineering , chemistry , composite material , physics , organic chemistry , thermodynamics , quantum , psychology , social psychology , genetics , quantum mechanics , biology , bacteria , engineering
The concept of stereocontrolled entanglements, in which the tunable H‐bonded chiral pairs serve as crosslinks to create topological constraints on the local chain dynamics, is introduced to tailor the crystalline morphology of stereocomplex poly(lactic acid). For the entanglements to be interconnected and activated, poly( d ‐lactic acid) with statistical branched architecture is incorporated, enabling the construction of 3D association with linear poly( l ‐lactic acid) chains. With thermodynamically graded disentanglement relaxation for the blends, the profound influence of entanglements on the crystalline morphology is revealed during isothermal crystallization. Orderly aligned cylindrites some with an exceptional length of over 500 μm, resembling the structural features of the classical shish‐kebab superstructure, are observed in the blends penetrated with dense entanglement constraints. By contrast, only dendritic spherulites are formed in the highly disentangled blends. The selectively suppressed homo‐crystallization by the entanglements offers insights into the contribution of constraints. This bottom‐up strategy opens up pathways to engender oriented crystals of long‐range order under quiescent conditions, which has potential implications for other chiral polymers.