TY - JOUR
T1 - Stretching PEO-PPO Type of Star Block Copolymer Gels
T2 - Rheology and Small-Angle Scattering
AU - Mortensen, Kell
AU - Annaka, Masahiko
N1 - Funding Information:
This work was funded from the Independent Research Fund Denmark, Technology and Production (DFF-4005-00112) and the Danish Research Infrastructure via DANSCATT (UFM-7055-00001B).
PY - 2018/12/18
Y1 - 2018/12/18
N2 - Cross-linked Tetronic star block copolymer gels, based on poly(ethylene oxide) and poly(propylene oxide), behave quite regular with respect to mechanical properties, but exhibits unusual absence of structural response to strain. The elastic response is linear up to more than 100% strain, with a steady-state modulus of the order of 0.01 MPa after an initial stress relaxation. Neutron and X-ray scattering experiments show a consistent but unexpected response to uniaxial strain, with no changes in characteristic molecular dimensions. Upon strain beyond about 100%, that is, when the stress-strain curve is no longer linear, structural texture appears and becomes even more pronounced upon further strain, thus, indicating alignment of the self-assembled hexagonally ordered cylindrical micelles with the cylinder-axis perpendicular to the strain. It is proposed that the main structural response to large-amplitude strain is related to a layer-dominated structure of cross-linked star molecules.
AB - Cross-linked Tetronic star block copolymer gels, based on poly(ethylene oxide) and poly(propylene oxide), behave quite regular with respect to mechanical properties, but exhibits unusual absence of structural response to strain. The elastic response is linear up to more than 100% strain, with a steady-state modulus of the order of 0.01 MPa after an initial stress relaxation. Neutron and X-ray scattering experiments show a consistent but unexpected response to uniaxial strain, with no changes in characteristic molecular dimensions. Upon strain beyond about 100%, that is, when the stress-strain curve is no longer linear, structural texture appears and becomes even more pronounced upon further strain, thus, indicating alignment of the self-assembled hexagonally ordered cylindrical micelles with the cylinder-axis perpendicular to the strain. It is proposed that the main structural response to large-amplitude strain is related to a layer-dominated structure of cross-linked star molecules.
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U2 - 10.1021/acsmacrolett.8b00792
DO - 10.1021/acsmacrolett.8b00792
M3 - Article
AN - SCOPUS:85057550305
VL - 7
SP - 1438
EP - 1442
JO - ACS Macro Letters
JF - ACS Macro Letters
SN - 2161-1653
IS - 12
ER -