Oxygen K edge scattering from bulk comb diblock copolymer reveals extended, ordered backbones above lamellar order-disorder transition
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Molecular Foundry
- Univ. of California, Irvine, CA (United States). Dept. of Chemical Engineering & Materials Sciences
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Molecular Foundry
The evolution of molecular morphology in bulk samples of comb diblock copolymer pNdc12-b-pNte21 across the lamellar order-disorder transition (ODT) is studied using resonant x-ray scattering at the oxygen K edge, with the goal of determining whether the molecules remain extended or collapse above the ODT. The distinct spectral resonances of carbonyl oxygen on the backbone and ether oxygen in the pNte side chains combine with their different site symmetry within the molecule to yield strong differences in bulk structural sensitivity at all temperatures. Comparison with simple models for the disordered phase clearly reveals that disordering at the ODT corresponds to loss of positional order of molecules with extended backbones that retain orientational order, rather than backbone collapse into a locally isotropic disordered phase. This conclusion is facilitated directly by the distinct structural sensitivity at the two resonances. Lastly, we discuss the roles of depolarized scattering in enhancing this sensitivity, and background fluorescence in limiting dynamic range, in oxygen resonant scattering.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC02-05CH11231
- OSTI ID:
- 1336911
- Report Number(s):
- LBNL-1006901; ir:1006901
- Journal Information:
- Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry, Journal Name: Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry; ISSN 1520-6106
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Similar Records
Phase structures and morphologies determined by competitions among self-organization, crystallization, and vitrification in a disordered poly(ethylene oxide)-{ital b}-polystyrene diblock copolymer
Influence of Charge Fraction on the Phase Behavior of Symmetric Single-Ion Conducting Diblock Copolymers