The structures of poly(oxyethylene)s having sulfone groups in the side chains

The structures of (-OCH2CHR-) with R = CH2S(CH2)(6)SO2(CH2)(M)H (ATP-M; M = 5,7,9) or R = CH2SO2(CH2)(6)SO2(CH2)(M)H (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 = similar to4.4 Angstrom, 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 similar to2.3 Angstrom 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 Angstrom for all the polymers except for ASP-5 (similar to 40 Angstrom). These values indicate that quasi-lon--range order exists in the smectic layers whose structures can be defined as smectic B (S-B). The d-spacing of the wide angle reflection, 4.4 Angstrom, 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 similar to 110 degreesC prior to the isotropic temperature at similar to 150 degreesC. Both the correlation length (from the wide angle reflection) and the layer thickness decreased from similar to 80 to similar to 30 Angstrom and from 46 to 40 Angstrom at this transition, respectively, indicating that the order in the smectic layers is lost and the S-B Structure has become a less ordered S-A structure at this transition. (C) 2001 Elsevier Science Ltd. All rights reserved.