Perforated Layer Structures in Liquid Crystalline Rod-coil Block Copolymers

Journal Article · Sat Jan 01 04:00:00 EST 2005 · J. Am. Chem. Soc.

DOI:https://doi.org/10.1021/ja053548k· OSTI ID:913904

Tenneti, K; Chen, X; Li, C; Tu, Y; Wan, X; Zhou, Q; Sics, I; Hsiao, B

We report a novel observation of the tetragonal perforated layer structures in a series of rod-coil liquid crystalline block copolymers (BCPs), poly(styrene-block-(2, 5-bis[4-methoxyphenyl]oxycarbonyl)styrene) (PS-b-PMPCS). PMPCS forms rigid rods while PS forms the coil block. Differential scanning calorimetry (DSC), polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), wide-angle X-ray diffraction (WAXD), and transmission electron microscopy (TEM) techniques were used to investigate these rod-coil molecules, and a perforated layer structure was observed at {sup fPMPCS} {approx} 0.37 in relatively low molecular weight (M{sub w}) samples and {approx}0.5 in high M{sub w} PS-b-PMPCS. This substantial phase boundary shift was attributed to the rod-coil nature of the BCP. The perforation obeys a tetragonal instead of hexagonal symmetry. The 'onset' of perforation was also observed in real space in sample PS{sub 272}-b-PMPCS{sub 93} ({sup fPMPCS} {approx} 0.52), in which few PS chains punctuate PMPCS layers. A slight increase in f{sub PS}, by blending with PS homopolymer, led to a dramatic change in the BCP morphology, and uniform tetragonal perforations were observed at {sup fPMPCS} {approx} 0.48.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 913904
• Report Number(s): BNL--78472-2007-JA
• Journal Information: J. Am. Chem. Soc., Journal Name: J. Am. Chem. Soc. Journal Issue: 44 Vol. 127; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COPOLYMERS
LIQUID CRYSTALS
MOLECULAR WEIGHT
MORPHOLOGY
POLYSTYRENE
SHAPE
national synchrotron light source