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Synthesis and characterization of non‐covalent liquid crystalline diblock copolymers
Author(s) -
Gohy JeanFrançois,
Antoun Sayed,
Sobry Roger,
Van den Bossche Guy,
Jérôme Robert
Publication year - 2000
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/(sici)1521-3935(20000101)201:1<31::aid-macp31>3.0.co;2-p
Subject(s) - copolymer , polymer chemistry , characterization (materials science) , covalent bond , polymer science , materials science , liquid crystalline , chemistry , polymer , nanotechnology , organic chemistry , composite material
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 proton‐transfer between a carboxylic acid‐containing mesogen (A) and the dimethylamino substituent of the polyDMAEMA block and by electrostatic interactions between the polyMA subunits and an ammonium‐containing mesogen (B). When mesogen A is complexed with DMAEMA units, a dramatic enhancement of the mesophase 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 composition. 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.