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Structure and phase behavior of a disk-necklace polymer: Cyclolinear polymethylsiloxane |
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| Authors: | Denis V Anokhin Yuli K Godovsky Sergei N Magonov Natalia N Makarova Wim Bras |
| Affiliation: | a Institut de Chimie des Surfaces et Interfaces (ICSI), UPR CNRS 9069, 15 rue Jean Starcky, B.P. 2488, 68057 Mulhouse Cedex, France b Department of Polymer Materials, Karpov Institute of Physical Chemistry, 10 Vorontsovo Pole, 105064 Moscow, Russia c Veeco Metrology Group, 112 Robin Hill Road, Santa Barbara, CA 93117, USA d Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov Street, 117813 Moscow, Russia e Estonian Nanotechnology Competence Center, Riia Street 142, 51014 Tartu, Estonia f Netherlands Organization for Scientific Research (NWO), DUBBLE-CRG/ESRF, B.P. 220, F-38043 Grenoble Cedex, France |
| Abstract: | The structure and phase transitions of cyclolinear polyorganosiloxane copolymer containing 12-member polysiloxane rings have been studied using synchrotron WAXS, DSC, TEM, variable-temperature AFM and polarized optical microscopy. The primary structure of this polymer can be viewed as a necklace of disk-shaped entities (cyclic groups) connected via flexible linkers.In the mesomorphic state, the presence of two different LC phases has been derived from the analysis of WAXS fiber diffractograms. The morphology of one of the phases shows a conventional hexagonal packing of LC chains where the chain axes are perpendicular to the plane of the 2D hexagonal lattice. The other one, so-called R-phase, has a vertically oriented rectangular 2D lattice formed by inter-chain correlations between the bulky polysiloxane cycles (disks). To our knowledge, such a disk-necklace mesophase in which the LC lattice is parallel to the backbone direction has not been reported in the literature so far. |
| Keywords: | Mesomorphic polymethylsiloxane Mesophase-assisted crystallization Disk-necklace polymer |
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