TY - JOUR
T1 - Frank–Kasper Phases Identified in PDMS-b-PTFEA Copolymers with High Conformational Asymmetry
AU - Jeon, Seungbae
AU - Jun, Taesuk
AU - Jo, Seongjun
AU - Ahn, Hyungju
AU - Lee, Seungwoo
AU - Lee, Byeongdu
AU - Ryu, Du Yeol
N1 - Funding Information:
S.J. and T.J. contributed equally to this work. This research was supported by the Samsung Research Funding Center of Samsung Electronics under the Project Number SRFC-MA1801-04.
PY - 2019/10/1
Y1 - 2019/10/1
N2 - 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.
AB - 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.
KW - Frank–Kasper phases
KW - block copolymers
KW - conformational asymmetry
KW - quasicrystals
KW - self-assembly
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U2 - 10.1002/marc.201900259
DO - 10.1002/marc.201900259
M3 - Article
C2 - 31584224
AN - SCOPUS:85072918846
VL - 40
JO - Macromolecular Rapid Communications
JF - Macromolecular Rapid Communications
SN - 1022-1336
IS - 19
M1 - 1900259
ER -