[en] Poly(dimethylaminoethylmethacrylate)-b-poly(sodium methacrylate) diblocks, (polyDMAEMA-b-polyMA), were synthesized as precursors of liquid crystalline (LC) copolymers. These LC copolymers were prepared by pro-ton-transfer between a carboxylic acid-containing meso-gen (A) and the dimethylamino substituent of the poly-DMAEMA block and by electrostatic interactions between the polyMA subunits and an ammonium-contain-ing mesogen (B). When mesogen A is complexed with DMAEMA units, a dramatic enhancement of the meso-phase stability is noted. The mesogenic properties of these LC copolymers were compared to those ones of the parent LC homopolymers, in relation to the copolymer composi-tion. The supramolecular organization of the LC diblock copolymers was studied by small-angle X-ray scattering (SAXS), and smectic mesophases were observed in some LC (co)polymers. For samples containing a major LC block, a smectic mesophase coexists with microphases formed by the second amorphous block. Different organizations, including a body-centered lattice of spheres and a hexagonal array of cylinders, were observed, depending on the investigated copolymers and their composition. When the LC block is the minor component, it forms microdomains too small for a liquid crystalline order to emerge. Moreover, no supramolecular organization of these dispersed microdomains was detected by SAXS. A homogeneous smectic mesophase was observed when the two blocks are bearing liquid crystalline moieties.
Center for Education and Research on Macromolecules (CERM)
Politique Scientifique Fédérale (Belgique) = Belgian Federal Science Policy ; The “Training and Mobility of Reseachers Program of the European Community" for support for SAXS measurements at L.U.R.E.