Frank-Kasper Phases Identified in PDMS-b-PTFEA Copolymers with High Conformational Asymmetry.
Macromol Rapid Commun
; 40(19): e1900259, 2019 Oct.
Article
em En
| MEDLINE
| ID: mdl-31584224
ABSTRACT
In the search for the formation of Frank-Kasper phases from diblock copolymer self-assembly, a series of compositionally asymmetric poly(dimethylsiloxane)-b-poly(2,2,2-triflouroethyl acrylate)s (PDMS-b-PTFEAs) are synthesized to produce PDMS-rich phases with PDMS volume fractions (fPDMS ) ranging from 0.746 to 0.869. As determined by small-angle X-ray scattering analysis, the Frank-Kasper σ and C14 phases are identified at fPDMS = 0.796 and 0.851, respectively, plausibly due to high conformational asymmetry (ε ≈ 2.20) between the two blocks. Intriguingly, the σ phase develops during heating from a short-range liquid-like packing (LLP) state, whereas the C14 phase is achieved at room temperature, which are both followed by a disordering at higher temperatures. Based on thermal experiments from a super cooled disordered state, the findings further provide compelling evidence of an LLP-hexagonally packed cylinder-σ transition and a direct pathway to the C14 phase during heating from an LLP state.
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01-internacional
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MEDLINE
Assunto principal:
Acrilatos
/
Dimetilpolisiloxanos
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Macromol Rapid Commun
Ano de publicação:
2019
Tipo de documento:
Article