Biaxial alignment of block copolymer-complex lamellae

Electronic Supplementary Material (ESI) for Soft Matter This journal is © The Royal Society of Chemistry 2012

Supporting information:

Biaxial alignment of block copolymer-complex lamellae Jingbo Wang, Wim H de Jeu, Maria Speiser, Andreas Kreyes, Ulrich Ziener, David Magerl, Martine Philipp, Peter Müller-Buschbaum, Martin Möller, and Ahmed Mourran*

[*] Corresponding-Author, E-mail: [email protected] Dr. Ahmed Mourran, Prof. Dr. Wim H. de Jeu, Jingbo Wang, Prof. Dr. Martin Möller DWI an der RWTH Aachen e.V., Forckenbeckstrasse 50, D-52056 Aachen, Germany. Maria Speiser, Dr. Andreas Kreyes, Prof. Dr. Ulrich Ziener, Institute of Organic Chemistry III–Macromolecular Chemistry, University of Ulm, Albert-Einstein-Allee 11, D-89075 Ulm, Germany. David Magerl, Dr. Martine Philipp, Prof. Dr. Peter Müller-Buschbaum Technische Universität München, Physik-Department, Lehrstuhl für Funktionelle Materialien, James-Franck-Strasse 1, 85748 Garching, Germany


3 2

0 . 2

(a)

0 . 1 5 . 0 0 3 1 0 2 1 0 1 1C 0/ e 0r u 1t a r 0e 9p n 0e 8T

0 7

0

0 06 . 0

g m / W m / C S D

5 . 1

1

g m / W m / C S D

g n i t a e H

°

1

g n i l o o C

-

0 5 1

0 0 1 C

/ e r u 0a t 5r e p n e T

0

0 5 2-

°

Figure S1. (a) Thermogram of ligand L1 indicating that the compound melts around 114 °C and recrystallizes around 69 °C with transition enthalpies of about 54 J/g, and 47 J/g, respectively. However, at low temperatures at least two thermal transitions are displayed,


probably due to reorganization of the octyl-tails. If the sample is quenched from the isotropic state to room temperature and heated back, only one melting peak occurs, located at 105 °C with a transition enthalpy of 54 J/g (see insert Figure S1a). SFM investigation of a thin film cast on SiO2 shows that L1 self-assembles in two distinct coexisting morphologies. (b) Layer-like structure with a depth of about 2.5 nm, as indicated by the black rectangle and the corresponding height distribution. (c) Enlarged area indicated by the arrow in (b), the image shows a strip-like structure with an in-plane periodicity of about 3.9 nm. Apparently, the ligand crystallizes in two polymorphs, which may coexist depending on the thermal history of the sample. The simplest model to explain the structure of the two polymorphs would be as follows. First dimers form stacks parallel to the substrate plane. Subsequently tilting of the long axes of the molecules relative to the plane of the layers is required as the length of L1, in the extended conformation (ca. 1.7 nm), is larger than the layer thickness. Stripes result from formation of a columnar phase (possible with multiple H-bonds) in which the inplane periodicity corresponds to the diameter of columns laying parallel to the substrate plane.1 It was not possible to prepare films of the ligand on PTFE rubbed SiO2 since the material spontaneously dewets on the substrate.


2 . 1

(a)

8 . 0 4 . 0

Cooling

0 . 0 4 . 0 -

g m / W m / C S D

Heating

8 . 0 0 0 1

5 7

0 5 C / e r u 5 a t 2 r e p m e 0 T

5 2 -

0 5 -

°

Figure S2. (a) Typical thermogram of ligand L2 indicating a single melting peak around 45 °C and recrystallization around 29 °C with transition enthalpies of about 31.2 J/g, and 30.8 J/g, respectively. (b) Optical micrograph of L2 at room temperature in crosspolarized light. The image shows a spherulitic texture common for crystalline compounds. (c) SFM height image of a thin film of L2 on silicon oxide. L2 forms a layered structure with an average step height of about 2.4 nm.


(a)

PS330-P4VP130(L1)0.75 PS330-P4VP130

(b)

PS330-P4VP130 L2

Abs./a.u.

Abs./a.u.

L1

1760 1720 1680 1640 1600 1560 1520 -1 Wavenumber/cm

PS330-P4VP130(L2)0.75

1760 1720 1680 1640 1600 1560 1520 -1 Wavenumber/cm

Figure S3. FTIR of (a) PS330-P4VP130(L1)0.75 and (b) PS330-P4VP130(L2)0.75 in the wavenumber region of 1520-1760 cm-1. Both spectra indicate that the absorption band of the carboxylic groups (C=O) of the pure ligand has shifted to higher wavenumbers (from 1720 cm-1 to 1730 cm-1 for L1; from 1650 cm-1 to 1690 cm-1 for L2) while in addition the bands broaden. The absorption band associated to the free pyridine ring (C=N, 1597 cm-1) shifts to ca. 1602 cm-1, indicating the formation of hydrogen bonds between the carboxylic groups and the nitrogen atoms of the pyridine units.2 There is no evidence for the presence of free ligands in the complex (within the accuracy of IR spectroscopy), though they cannot be excluded as the absorption band of the carboxylic groups is quite broad. For a similar system saturation has been reported for a degree of complexation of about 0.7-0.75.3, 4


Figure S4. SFM phase images of a thin film deposited on rubbed PTFE after annealing in benzene vapor for 24h: (a) PS190-P4VP100 (L1)0.75 on PTFE (scan size 6 μm2 in 4096×4096 lines), insert shows the 2D FFT. (b) Enlarged view of (a) (scan size 2×2 μm2 in 512×512 lines). The film thickness is 80 nm and the lamellar period 26 nm. The arrow indicates the rubbing direction.


Figure S5. Left: GIWAXS of PS330-P4VP130(L2)0.75 with at the right corresponding sliceintegrated results over 80-100o. Oriented samples with the x-ray beam parallel (a, b) and perpendicular (c, d) to the preferred PTFE direction, respectively. The broad band is due to the internal short-range order of the ligand lamellae, similar as for the non-oriented sample. The additional peaks are due to the underlying PTFE structure, as highlighted by the hexagonal structure in (a) and in the insert in (d). In (b) the positions of the center of the broad peak and the narrow one from the PTFE structure are 13.6 and 12.8 nm–1, respectively.


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