Block Copolymers with a Twist

Journal Article · Thu Jan 01 04:00:00 EST 2009 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja9083804· OSTI ID:1019826

Ho, R; Chiang, Y; Chen, C; Wang, H; Hasegawa, H; Akasaka, S; Thomas, E; Burger, C; Hsiao, B

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.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: DOE - OFFICE OF SCIENCE
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1019826
• Report Number(s): BNL--95672-2011-JA
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 51 Vol. 131; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ANNEALING
COPOLYMERS
ELECTRONS
PHASE DIAGRAMS
RACEMATES
SYMMETRY
TOMOGRAPHY
national synchrotron light source