Synthesis and liquid crystalline properties of poly(ethylene oxide) brushes with amphiphilic side groups

Poly(ethlene oxide)s containing decythiomethyl (DTP), decylsulfonylmethyl (DSP), methyl-oligo(ethylene oxide) thiomethyl (MnOTP), methyl-oligo(ethylene oxide) sulfonylmethyl (MnOSP), decyl-oligo(ethylene oxide) sulfonylmenthyl (MnOTP), decyl-oligo(ethylene oxide) sulfonyl-methyl (DnOSP) groups in the side-chains, where n (the number of ethylene oxide units) = 1,2,3 or 4 for DnOTP and DnOSP, and n = 2,3, or 7 for MnOTP and MnOSP, were sythesized to study the effect of the structure of the side-chains on the ordered phases of the polymers. All of the MnOSPs, as well as M2OTP and M3OTP, were found to be amorphous. DTP, M7OTP, D1OTP, D2OTP, and D4OTP were found to be amorphous polymers. DTP, M7OTP, D1OTP, D2OTP and D4OTP were found to be liquid crystalline. Therefore, the phase seperation facilitated by the introduction of the sulfone group and/or by the addition of the longer ethylene oxide units between the ethylene oxide backbones and the hydrophobic decyl tails were found to be a key factor in the formation of the liquid crystalline phases. These orders phases were characterized using differential scanning calorimetry, polarized optical microscopy, and X-ray diffraction.