Aqueous bilayers of glutamate-based double-chain ammonium amphiphiles ii. improvement of polymerization and membrane characteristics by ether-linked alkyl tails

Photopolymerization was conducted for aqueous bilayer membranes of glutamate-based double-chain ammonium amphiphiles which have the ether linkage in the alkyl tail portion and the acrylate moiety attached to the ammonium head. The polymerization readily proceeded to completion (Mw∼10⁷) in contrast to that of related bilayers which lack the ether linkage. The reactivity difference was particularly large in the polymerization in the crystalline state. According to DSC measurement, circular dichroism, and fluorescence spectroscopy, the bilayer polymerized in the liquid crystalline state showed lessened side chain alignment, whereas regular side-chain packing was maintained in the polymerization in the crystalline state. Re-dispersion in water was not possible for the former polymer, though possible for the latter. These different properties may be attributed to the steric difference in the main chain portion which, however, could not be detected by 400 MHz ¹H-NMR spectroscopy.