Poly(ethylene oxide-b-isoprene) diblock copolymer phase diagram

G. Floudas; B. Vazaiou; F. Schipper; R. Ulrich; U. Wiesner; H. Iatrou; N. Hadjichristidis

doi:10.1021/ma001957p

Poly(ethylene oxide-b-isoprene) diblock copolymer phase diagram

G. Floudas^*, B. Vazaiou, F. Schipper, R. Ulrich, U. Wiesner, H. Iatrou, N. Hadjichristidis

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

146 Scopus citations

Abstract

The phase state of 25 poly(ethylene oxide-b-isoprene) (PEO-PI) diblock copolymers spanning the composition range 0.05 < f_PEO < 0.8 has been studied using small-angle X-ray scattering and theology. In addition, the thermal and thermodynamic properties have been obtained from differential scanning calorimetry and pressure-volume-temperature measurements. Twenty of the diblocks exhibit at least one order-to-order transition, and two show four ordered phases. The phase diagram consists of four equilibrium phases in the melt; lamellar (Lam), hexagonally packed cylinders (Hex), spheres packed in a body centered cubic lattice (bcc) and a bicontinuous cubic phase with the Ia3̄d space group symmetry known as the gyroid phase. The latter is formed for the range of compositions 0.4 < f_PEO < 0.45 which are the highest ever reported for a stable gyroid phase. The high asymmetry in the present phase diagram is attributed to the high conformational asymmetry of the PEO and PI (ε = 2.72). At low temperatures, upon PEO crystallization, all phases revert to the crystalline lamellar structure (L_c). Within the composition range 0.66 < f_PEO < 0.7 another intermediate phase is formed known as perforated layers (PL) which is clearly not an equilibrium phase. The thermal expansion coefficient was found to be a sensitive probe of the ordered microstructures.

Original language	English (US)
Pages (from-to)	2947-2957
Number of pages	11
Journal	Macromolecules
Volume	34
Issue number	9
DOIs	https://doi.org/10.1021/ma001957p
State	Published - Apr 24 2001
Externally published	Yes

ASJC Scopus subject areas

Materials Chemistry
Polymers and Plastics
Inorganic Chemistry
Organic Chemistry

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10.1021/ma001957p

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title = "Poly(ethylene oxide-b-isoprene) diblock copolymer phase diagram",

abstract = "The phase state of 25 poly(ethylene oxide-b-isoprene) (PEO-PI) diblock copolymers spanning the composition range 0.05 < fPEO < 0.8 has been studied using small-angle X-ray scattering and theology. In addition, the thermal and thermodynamic properties have been obtained from differential scanning calorimetry and pressure-volume-temperature measurements. Twenty of the diblocks exhibit at least one order-to-order transition, and two show four ordered phases. The phase diagram consists of four equilibrium phases in the melt; lamellar (Lam), hexagonally packed cylinders (Hex), spheres packed in a body centered cubic lattice (bcc) and a bicontinuous cubic phase with the Ia{\=3}d space group symmetry known as the gyroid phase. The latter is formed for the range of compositions 0.4 < fPEO < 0.45 which are the highest ever reported for a stable gyroid phase. The high asymmetry in the present phase diagram is attributed to the high conformational asymmetry of the PEO and PI (ε = 2.72). At low temperatures, upon PEO crystallization, all phases revert to the crystalline lamellar structure (Lc). Within the composition range 0.66 < fPEO < 0.7 another intermediate phase is formed known as perforated layers (PL) which is clearly not an equilibrium phase. The thermal expansion coefficient was found to be a sensitive probe of the ordered microstructures.",

author = "G. Floudas and B. Vazaiou and F. Schipper and R. Ulrich and U. Wiesner and H. Iatrou and N. Hadjichristidis",

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T1 - Poly(ethylene oxide-b-isoprene) diblock copolymer phase diagram

AU - Floudas, G.

AU - Vazaiou, B.

AU - Schipper, F.

AU - Ulrich, R.

AU - Wiesner, U.

AU - Iatrou, H.

AU - Hadjichristidis, N.

PY - 2001/4/24

Y1 - 2001/4/24

N2 - The phase state of 25 poly(ethylene oxide-b-isoprene) (PEO-PI) diblock copolymers spanning the composition range 0.05 < fPEO < 0.8 has been studied using small-angle X-ray scattering and theology. In addition, the thermal and thermodynamic properties have been obtained from differential scanning calorimetry and pressure-volume-temperature measurements. Twenty of the diblocks exhibit at least one order-to-order transition, and two show four ordered phases. The phase diagram consists of four equilibrium phases in the melt; lamellar (Lam), hexagonally packed cylinders (Hex), spheres packed in a body centered cubic lattice (bcc) and a bicontinuous cubic phase with the Ia3̄d space group symmetry known as the gyroid phase. The latter is formed for the range of compositions 0.4 < fPEO < 0.45 which are the highest ever reported for a stable gyroid phase. The high asymmetry in the present phase diagram is attributed to the high conformational asymmetry of the PEO and PI (ε = 2.72). At low temperatures, upon PEO crystallization, all phases revert to the crystalline lamellar structure (Lc). Within the composition range 0.66 < fPEO < 0.7 another intermediate phase is formed known as perforated layers (PL) which is clearly not an equilibrium phase. The thermal expansion coefficient was found to be a sensitive probe of the ordered microstructures.

AB - The phase state of 25 poly(ethylene oxide-b-isoprene) (PEO-PI) diblock copolymers spanning the composition range 0.05 < fPEO < 0.8 has been studied using small-angle X-ray scattering and theology. In addition, the thermal and thermodynamic properties have been obtained from differential scanning calorimetry and pressure-volume-temperature measurements. Twenty of the diblocks exhibit at least one order-to-order transition, and two show four ordered phases. The phase diagram consists of four equilibrium phases in the melt; lamellar (Lam), hexagonally packed cylinders (Hex), spheres packed in a body centered cubic lattice (bcc) and a bicontinuous cubic phase with the Ia3̄d space group symmetry known as the gyroid phase. The latter is formed for the range of compositions 0.4 < fPEO < 0.45 which are the highest ever reported for a stable gyroid phase. The high asymmetry in the present phase diagram is attributed to the high conformational asymmetry of the PEO and PI (ε = 2.72). At low temperatures, upon PEO crystallization, all phases revert to the crystalline lamellar structure (Lc). Within the composition range 0.66 < fPEO < 0.7 another intermediate phase is formed known as perforated layers (PL) which is clearly not an equilibrium phase. The thermal expansion coefficient was found to be a sensitive probe of the ordered microstructures.

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Poly(ethylene oxide-b-isoprene) diblock copolymer phase diagram

Abstract

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