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Block copolymers with a twist.
Ho, Rong-Ming; Chiang, Yeo-Wan; Chen, Chun-Ku; Wang, Hsin-Wei; Hasegawa, Hirokazu; Akasaka, Satoshi; Thomas, Edwin L; Burger, Christian; Hsiao, Benjamin S.
Afiliação
  • Ho RM; Department of Chemical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan. rmho@mx.nthu.edu.tw
J Am Chem Soc ; 131(51): 18533-42, 2009 Dec 30.
Article em En | MEDLINE | ID: mdl-20028149
Chiral block copolymers (BCPs*) comprising chiral entities were designed to fabricate helical architectures (i.e., twisted morphologies) from self-assembly. A new helical phase (H*) with P622 symmetry was discovered in the self-assembly of poly(styrene)-b-poly(l-lactide) (PS-PLLA) BCPs*. Hexagonally packed, interdigitated PLLA helical microdomains in a PS matrix were directly visualized by electron tomography. The phase diagram of the PS-PLLA BCPs* was also established. Phase transitions from the H* phase to the stable cylinder and gyroid phases were found after long-time annealing, suggesting that the H* is a long-lived metastable phase. In contrast to racemic poly(styrene)-b-poly(d,l-lactide) BCPs, chiral interaction significantly enhances the incompatibility between achiral PS and chiral PLLA blocks in the PS-PLLA BCPs* and can be estimated through the determination of the interaction parameter.

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Idioma: En Revista: J Am Chem Soc Ano de publicação: 2009 Tipo de documento: Article

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Idioma: En Revista: J Am Chem Soc Ano de publicação: 2009 Tipo de documento: Article