Synthesis and dipole–dipole interaction-induced mesomorphic behavior of poly(oxyethylene)s containing (n-octylsulfonyl)alkylthiomethyl or (n-octylsulfonyl)alkylsulfonylmethyl side groups

Two series of ((n-octylsulfonyl)alkylthio)methyl-substituted poly(oxyethylene)s ((–OCH2CHR–)n, where R=–CH2S(CH2)MSO2(CH2)8H) (OTP-M, M=3,4,5,6,7,9,12), and ((n-octylsulfonyl)alkylsulfonyl)methyl-substituted poly(oxyethylene) ((–OCH2CHR–)n, where R=–CH2SO2–(CH2)MSO2(CH2)8H) (OSP-M, M=3,4,5,6,7,9,12), were synthesized using polymer analogous reactions from poly(epichlorohydrin) to study the effect of dipole–dipole interactions of the sulfone groups (SO2) on the ordered structures of the poly(oxyethylene) derivatives. The ordered phases of these polymers were studied using polarizing optical microscopy, X-ray diffraction, differential scanning calorimetry and IR spectroscopy. OTP-Ms and OSP-3 showed ordered phases originated from side chain crystallization, while OSP-Ms except OSP-3 showed liquid crystalline behavior. The poly(oxyethylene) derivatives with M=5,6,7 had double-layer structures, while the polymers with M=3,4,9,12 had intercalating double-layer structures at room temperature. The layer structures of the poly(oxyethylene) derivatives were found to be affected by the positions of the side chain sulfone groups which can generate strong dipole–dipole interactions.