Abstract
The structures of (-OCH2CHR-) with R = CH2S(CH2)6SO2(CH2) MH (ATP-M; M = 5,7,9) or R = CH2SO2(CH2)6SO2(CH 2)MH (ASP-M; M = 5,7,9) were studied using X-ray diffraction and differential scanning calorimetry. The X-ray patterns of all ATPs and ASPs studied show a series of ordered reflections in the small angle region and a sharp wide angle reflection at d = ≁4.4 Å, characteristic of a smectic phase. The smectic layer thickness corresponds to twice the most extended side chain length and linearly increases as the side chain length increases with a slope of ∼2.3 Å per methylene spacer. This indicates that all ASPs and ATPs studied have a double layer structure with side chains normal to the main chain and probably an all-trans conformation of the side chains. The correlation lengths measured from the wide angle reflections are in the range of 80 ± 10 Å for all the polymers except for ASP-5 (∼40 Å). These values indicate that quasi-longo-range order exists in the smectic layers whose structures can be defined as smectic B (SB). The d-spacing of the wide angle reflection, 4.4 Å, suggests that paraffinic side chain crystallization does not occur and that the smectic mesophase develops through dipole-dipole interactions of sulfone groups in the side chains. During heating, ATP-5 shows recrystallization after the first melting. The structure produced during recrystallization has a similar smectic structure but with more dense packing between side chains than before the first melting. In the case of ASP-9, a smectic to smectic transition was observed at ∼110°C prior to the isotropic temperature at ∼150°C. Both the correlation length (from the wide angle reflection) and the layer thickness decreased from ∼80 to ∼30 Å and from 46 to 40 Å at this transition, respectively, indicating that the order in the smectic layers is lost and the SB structure has become a less ordered SA structure at this transition.
Original language | English |
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Pages (from-to) | 177-183 |
Number of pages | 7 |
Journal | Polymer |
Volume | 43 |
Issue number | 1 |
DOIs | |
State | Published - 12 Oct 2001 |
Keywords
- Liquid crystal
- Poly(oxyethylene)
- X-ray diffraction