Registry No. (C18) (maleic anhydride) (alternating copolymer, lithium salt), 113109-85-6; (C16)(maleic anhydride) (alternating copolymer, lithium salt), 115678-69-8; (C14)(maleic anhydride) (alternating copolymer, lithium salt), 115678-71-2; (C12)(maleic anhydride) (alternating copolymer, lithium salt), 115678-73-4; (C10)(maleic anhydride) (alternating copolymer, lithium salt), 115792-89-7; (C8) (maleic anhydride) (alternating copolymer, lithium salt), 115678-74-5.

A microscopic statistical theory of a symmetrical polyelectrolyte complex (PEC) is developed. PEC is shown to form a polymer globule. The equilibrium density of PEC, the width of a PEC surface layer, and the surface tension of PEC are calculated as a function of salt concentration. Description of PEC as a polymer globule enables us to simplify theoretical treatment of the phenomenon of phase separation in polyelectrolyte solutions (complex coacervation). Numerous experimental facts concerning complex coacervation are easily explained within this approach. Complex coacervation is considered as precipitation of polymer globules owing to minimization of surface energy. The theory is based on the Lifshitz-Grosberg theory of polymer globules and our previous work concerning the equation of state of polyelectrolyte solutions. It is limited to the case of polyions with the low linear density of charge, which is most clear from the theoretical point of view and is also of practical and, in particular, of biological interest.

Materials with a macroscopic electric polarization display a variety of useful properties, such as piezo-and pyroelectricity and second-order nonlinear optical activity 1 . Macroscopic polarization results when dipolar molecules are orientated in the same direction, or when ions are organized in a non-centrosymmetric crystal structure 2 . Centrosymmetric molecules have no dipole moment and so cannot generate a macroscopic polarization. Non-centrosymmetry in amorphous materials can be engineered by depositing particular sequences of layers on top of each other, or by applying external ®elds (generally electric) to orientate the molecules 3 . Here we report the formation of a non-centrosymmetric structure in an amorphous material through spontaneous selfassembly. Block copolymers are known to form ordered structures at the microscale owing to segregation of the different blocks 4,5 . We show that a mixture of a ternary triblock copolymer and a binary diblock copolymer will organize itself into a noncentrosymmetric layered structure in which the layers are occupied by different blocks. The structure is periodic with a length scale of around 60 nm.The formation of liquid-crystalline non-centrosymmetric materials from molecules which are themselves non-centrosymmetric but not chiral has been much debated in the past two decades 6,7 . In particular, molecules consisting of three or four sub-groups, a±b±g and a±b±g±a have been suggested as good candidates to obtain longitudinal ferroelectric smectics 8±10 (that is, materials where noncentrosymmetric molecules self-assemble into stacks of liquid-like layers with all the molecules being orientated in the same direction). Such materials have been synthesized and studied 11,12 . Achiral banana-shaped molecules forming antiferroelectric chiral smectics have been reported, which can be transformed into ferroelectric materials by application of an electric ®eld 13,14 . In the case of lowmolecular-weight self-assembling compounds, smectic periodicity lies in the range of a few nanometres. To achieve smectic order with larger layer thickness (and thus larger periodicity) through selfassembling, it is natural to use linear block copolymers: these molecules consist of long sequences of chemically different monomers linked together by a covalent bond. Thanks to the improvement of synthetic techniques, it is now possible to make A±B±C triblock copolymers with well controlled molecular architecture, that is, with well controlled block lengths. Depending on the chemical structure and the length of blocks, these molecules form very interesting mesophases 15±20 . In most cases, centrosymmetric structures have been observed. The only exception reported so far was a helical morphology, where the occurrence of right-and lefthanded helices suppressed the formation of a well developed longrange-ordered structure 21 . One of us (R.S.) has proposed that by mixing suitably chosen A±B±C triblock copolymers with A±C diblock copolymers it should be possible to obtain self-assembled non-centrosymme...

On lyotropic behavior of molecular bottle-brushes Saariaho, M.; Ikkala, O.; Szleifer, I.; Erukhimovich, I.; ten Brinke, G. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. A three dimensional continuous space Monte Carlo computer simulation study is presented to discuss the extension of flexible, linear polymer chains due to the presence of equally flexible side chains. We consider the enhancement of the persistence length of bottle-brush structures in an athermal solution due to steric interactions between the side chains. The largest structure studied consists of a backbone of 100 beads with 50 side chains of 20 beads each. The persistence length is evaluated in two different ways using the radius of gyration of the backbone and the bond angle correlation function, respectively. A correct description of the backbone conformations is shown to require at least two characteristic lengths. At a small length scale the backbone behaves flexible; the extension occurs at a larger length scale. There is a strong indication that the ratio between the persistence length and the diameter, which is the determining factor for lyotropic behavior of conventional semiflexible chains, levels off as a function of the side chain length. The value of this ratio is, moreover, too small to induce lyotropic behavior along this line. Recent experimental observations of lyotropic behavior of polymacromonomers are discussed in terms of these findings.

The microphase separation in melts of asymmetric triblock and trigraft, periodic polyblock and polygraft, and star-shaped copolymers of two types ((An)*(Bm)* and (A"Bm)*) is investigated within the framework of the mean field approximation. To enable rapid comparison of the behavior of various types of block copolymer architecture, a special program "Supercrystal" using previously calculated higher correlators of specific systems is elaborated. Surfaces of phase transition between phases with different supercrystal symmetry and a spatially homogeneous state are constructed as a function of molecular architecture and the Flory parameter . A behavior similar to a tricritical one is observed in melts of star-shaped copolymers of the kind (A")*(Bm)* with k > 5, k being the number of arms. Phase diagrams obtained for the other systems are like the phase diagram obtained by Leibler for the molten diblock copolymer, but the temperatures of the phase transitions differ considerably for copolymers consisting of the same blocks connected in a different manner.There are limiting phase diagrams for both polyblock and polygraft systems in the limit k -* °°, k being the number of blocks A"Bm in a chain.