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Lamellar Diblock Copolymer Thin Films during Solvent Vapor Annealing Studied by GISAXS: Different Behavior of Parallel and Perpendicular Lamellae.

Zhang J, Posselt D, Smilgies DM, Perlich J, Kyriakos K, Jaksch S, Papadakis CM - Macromolecules (2014)

Bottom Line: During annealing with ethyl acetate (EAC) vapor, it is found that perpendicular lamellae behave differently from parallel ones, which is due to the fact that their initial lamellar thicknesses differ strongly.The first two regimes of swelling are associated with a significant structural rearrangement of the lamellae; i.e., the lamellae first become thicker, and then perpendicular and randomly oriented lamellae vanish, which results in a purely parallel orientation at the end of the swelling process.During drying, the deswelling is nonaffine which may be a consequence of the increase of nonfavorable segmental interactions as the solvent is removed.

View Article: PubMed Central - PubMed

Affiliation: Physik-Department, Fachgebiet Physik weicher Materie, Technische Universität München , James-Franck-Str. 1, 85748 Garching, Germany.

ABSTRACT
The reorientation of lamellae and the dependence of the lamellar spacing, D lam, on polymer volume fraction, ϕP, D lam ∝ ϕP (-β), in diblock copolymer thin films during solvent vapor annealing (SVA) are examined by combining white light interferometry (WLI) and grazing-incidence small-angle X-ray scattering (GISAXS). A thin film of lamellae-forming poly(styrene-b-butadiene) prepared by spin-coating features lamellae of different orientations with the lamellar spacing depending on orientation. During annealing with ethyl acetate (EAC) vapor, it is found that perpendicular lamellae behave differently from parallel ones, which is due to the fact that their initial lamellar thicknesses differ strongly. Quantitatively, the swelling process is composed of three regimes and the drying process of two regimes. The first two regimes of swelling are associated with a significant structural rearrangement of the lamellae; i.e., the lamellae first become thicker, and then perpendicular and randomly oriented lamellae vanish, which results in a purely parallel orientation at the end of the swelling process. The rearrangement is attributed to the increase of mobility of the polymer chains imparted by the solvent and to a decrease of total free energy of the thin film. In the third regime of swelling, the scaling exponent is found to be β = -0.32. During drying, the deswelling is nonaffine which may be a consequence of the increase of nonfavorable segmental interactions as the solvent is removed.

No MeSH data available.


Related in: MedlinePlus

Lamellar spacings, Dlampar (open black circles) and Dlamperp (red solid circles),as a function of the polymer volume fraction,ϕP, in a double-logarithmic representation duringswelling (a) and drying (b). The full lines are linear fits. The backgroundcolors indicate the different regimes marked by Roman numbers. Thecorresponding times are given on the top axis of the profiles. Thearrow indicates the polymer concentration at which the glass transitiontemperature of PS block reaches room temperature.
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fig5: Lamellar spacings, Dlampar (open black circles) and Dlamperp (red solid circles),as a function of the polymer volume fraction,ϕP, in a double-logarithmic representation duringswelling (a) and drying (b). The full lines are linear fits. The backgroundcolors indicate the different regimes marked by Roman numbers. Thecorresponding times are given on the top axis of the profiles. Thearrow indicates the polymer concentration at which the glass transitiontemperature of PS block reaches room temperature.

Mentions: To quantify the dependence of the lamellar spacing, Dlam, on the polymer volume fraction, ϕP, Dlam ∝ ϕP–β, we have plotted Dlampar and Dlamperp during SVAas a function of ϕP in a log–log representation(Figure 5). For the behavior of the parallellamellae, three regimes are identified: (I) slow swelling following Dlampar ∝ ϕP–2.2±0.3 for 0.95 < ϕP <1, (II) faster swelling following Dlampar ∝ ϕP–5.1±0.3 for 0.87 < ϕP < 0.95, and (III) a slow deswellingfollowing Dlampar ∝ ϕP0.32±0.3 for 0.77 < ϕP < 0.83. These regimes are indicated in Figure 5 by different colors, and the corresponding timesare given in the top axis.


Lamellar Diblock Copolymer Thin Films during Solvent Vapor Annealing Studied by GISAXS: Different Behavior of Parallel and Perpendicular Lamellae.

Zhang J, Posselt D, Smilgies DM, Perlich J, Kyriakos K, Jaksch S, Papadakis CM - Macromolecules (2014)

Lamellar spacings, Dlampar (open black circles) and Dlamperp (red solid circles),as a function of the polymer volume fraction,ϕP, in a double-logarithmic representation duringswelling (a) and drying (b). The full lines are linear fits. The backgroundcolors indicate the different regimes marked by Roman numbers. Thecorresponding times are given on the top axis of the profiles. Thearrow indicates the polymer concentration at which the glass transitiontemperature of PS block reaches room temperature.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4150605&req=5

fig5: Lamellar spacings, Dlampar (open black circles) and Dlamperp (red solid circles),as a function of the polymer volume fraction,ϕP, in a double-logarithmic representation duringswelling (a) and drying (b). The full lines are linear fits. The backgroundcolors indicate the different regimes marked by Roman numbers. Thecorresponding times are given on the top axis of the profiles. Thearrow indicates the polymer concentration at which the glass transitiontemperature of PS block reaches room temperature.
Mentions: To quantify the dependence of the lamellar spacing, Dlam, on the polymer volume fraction, ϕP, Dlam ∝ ϕP–β, we have plotted Dlampar and Dlamperp during SVAas a function of ϕP in a log–log representation(Figure 5). For the behavior of the parallellamellae, three regimes are identified: (I) slow swelling following Dlampar ∝ ϕP–2.2±0.3 for 0.95 < ϕP <1, (II) faster swelling following Dlampar ∝ ϕP–5.1±0.3 for 0.87 < ϕP < 0.95, and (III) a slow deswellingfollowing Dlampar ∝ ϕP0.32±0.3 for 0.77 < ϕP < 0.83. These regimes are indicated in Figure 5 by different colors, and the corresponding timesare given in the top axis.

Bottom Line: During annealing with ethyl acetate (EAC) vapor, it is found that perpendicular lamellae behave differently from parallel ones, which is due to the fact that their initial lamellar thicknesses differ strongly.The first two regimes of swelling are associated with a significant structural rearrangement of the lamellae; i.e., the lamellae first become thicker, and then perpendicular and randomly oriented lamellae vanish, which results in a purely parallel orientation at the end of the swelling process.During drying, the deswelling is nonaffine which may be a consequence of the increase of nonfavorable segmental interactions as the solvent is removed.

View Article: PubMed Central - PubMed

Affiliation: Physik-Department, Fachgebiet Physik weicher Materie, Technische Universität München , James-Franck-Str. 1, 85748 Garching, Germany.

ABSTRACT
The reorientation of lamellae and the dependence of the lamellar spacing, D lam, on polymer volume fraction, ϕP, D lam ∝ ϕP (-β), in diblock copolymer thin films during solvent vapor annealing (SVA) are examined by combining white light interferometry (WLI) and grazing-incidence small-angle X-ray scattering (GISAXS). A thin film of lamellae-forming poly(styrene-b-butadiene) prepared by spin-coating features lamellae of different orientations with the lamellar spacing depending on orientation. During annealing with ethyl acetate (EAC) vapor, it is found that perpendicular lamellae behave differently from parallel ones, which is due to the fact that their initial lamellar thicknesses differ strongly. Quantitatively, the swelling process is composed of three regimes and the drying process of two regimes. The first two regimes of swelling are associated with a significant structural rearrangement of the lamellae; i.e., the lamellae first become thicker, and then perpendicular and randomly oriented lamellae vanish, which results in a purely parallel orientation at the end of the swelling process. The rearrangement is attributed to the increase of mobility of the polymer chains imparted by the solvent and to a decrease of total free energy of the thin film. In the third regime of swelling, the scaling exponent is found to be β = -0.32. During drying, the deswelling is nonaffine which may be a consequence of the increase of nonfavorable segmental interactions as the solvent is removed.

No MeSH data available.


Related in: MedlinePlus