Non-amphiphilic polymers

The non-amphiphilic polymers can be widely considered as homopolymers or random copolymers. Most of the studies focussed on water-soluble polymers, but some studies on oil-soluble polymers exist as well. The water-soluble polymers can be uncharged or 

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C. Prata, F. Giusti, Y. Gohon, B. Pucci, J.-L. Popot, C. Tribet (2001) Non-ionic amphiphilic polymers derived from Tris(hydroxymethyl)-acrylamidomethane keep membrane proteins soluble and native in the absence of detergent. Biopolymers, 56 77-84... 

Attaching non amphiphilic or amphiphilic liquid crystalline molecules as side chains to linear, branched or crosslinkedpolymers yields liquid crystal (l.c.) side chain polymers, which can exhibit the liquid crystalline state analogously to the conventional low molar mass liquid crystals. The l.c.-side chain polymers combine the specific, anisotropic properties of the liquid crystalline state with the specific properties of polymers. 

The systematic synthesis of non amphiphilic l.c.-side chain polymers and detailed physico-chemical investigations are discussed. The phase behavior and structure ofnematic, cholesteric and smectic polymers are described. Their optical properties and the state of order of cholesteric and nematic polymers are analysed in comparison to conventional low molar mass liquid crystals. The phase transition into the glassy state and optical characterization of the anisotropic glasses having liquid crystalline structures are examined. 

In the first part of this paper we will give a review on our experimental work on non amphiphilic l.c. side chain polymers and will compare their properties with the corresponding l-l.c. s. In the second part results on amphiphilic side chain polymers will be discussed. 

Non Amphiphilic L.C. Side Chain Polymers 2.1 Model Considerations and Synthesis... 

Approaches to artificial ion channels have, for instance, made use of macrocyclic units [6.72,6.74] (see also below), of peptide [8.183-8.185] and cyclic peptide [8.186] components, of non-peptidic polymers [8.187] and of various amphiphilic molecules [6.11, 8.188, 8.189]. The properties of such molecules incorporated in bilayer membranes may be studied by techniques such as ion conductance [6.69], patch-clamp [8.190] or NMR [8.191, 8.192] measurements. However, the nature of the superstructure formed and the mechanism of ion passage (carrier, channel, pore, defect) are difficult to determine and often remain a matter of conjecture. 

When the macromonomer is an amphiphilic polymer, its polymerization in the polar media is unusually rapid as a result of its organization into micelles. Under such conditions, the unsaturated groups are concentrated in the micelle they mostly form the hydrophobic core of aggregates (micelles). During the polymerization, the non-polymerizing micelles and/or the monomer saturated continuous phase act as a monomer reservoir. 

Polymer adsorption has also been adapted to QCM sensing whereby biofunctional thin films are adsorbed on the crystal surface with non-specific binding controlled by tuning of polymer composition. This approach proved successful as applied to carbohydrate-protein interaction by Matsuura et al. through adsorption of lactose bearing amphiphilic polymers on hydrophobic surfaces which then showed RCA12o and peanut lectin (PNA) affinity [33]. Carbohydrate surfaces prepared by photo insertion into an adsorbed polymer were tested by QCM and showed the predicted affinities [34] while in another example a covalently bound glycopolymer demonstrated Concanavalin A detection ability [35]. 

Another improvement of the solubilisation has been accomplished by adding short amphiphilic block copolymers in low concentration (see Section 4.2 for details). Briefly, these polymers have a polyethylene-propylene hydrophobic block and a polyethylene oxide head group and are thus similar to the ethoxylated non-ionic surfactants to which these are added. The main difference is that the two blocks of the amphiphilic polymer are several times larger than the corresponding low molecular weight surfactant. The role of these polymers is to increase the reach of the amphiphilic layer such that it extends deeper into both the oil and the aqueous phase in accordance with Winsor s premise. As a consequence, they are found to notably increase solubilisation [50]. As seen in Fig. 3.9(c), these additives could be called amphiphilic linkers since they act upon both sides of the interface. 

Fig. 3a-f. Synthetic strategies to polysoaps a polymerization of reactive surfactants [51] b polycondensation of non-amphiphilic reagents [119,120] c grafting of surfactant fragments [121,122] d hydrophobization of preformed polymers [49, 52, 75, 130, 131, 138, 139, 141, 142, 146] e copolymerization of reactive surfactants with polar monomers [156] f copolymerization of hydrophobic and hydrophilic monomers [53]... 

Ikegami and co-workers have prepared assembled complexes of palladium and a non-cross-linked amphiphilic polymer (Scheme 64).The material, denoted as PdAS, was prepared by reaction of (NH4)2PdCl4 with poly-[iV-isopropylacrylamide)-fo-(4-diphenylstyrylphosphine)], itself made by random co-polymerization of 4-diphenyl-... 

More conveniently, reaction can be carried out in water without a cosolvent under certain conditions. Coupling of substrates insoluble in water such as 30 proceeds with TON up to 20000 in water when an insoluble and assembled Pd catalyst and a non-cross-linked amphiphilic (amphiphilic) polymer, containing diphenylphosphine group, are used. The catalyst system was used 10 times without any decrease in activity [44]. Also an amphiphilic resin-supported Pd catalyst can be used in water many times giving nearly quantitative yields of coupling products [45]. 

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