Polyelectrolyte Properties

Usually the acid-base properties of poly electrolyte are studied by potentiometric titrations. However it is well known, that understanding of polyelectrolyte properties in solution is based on the knowledge of the thermodynamic properties. Up to now, there is only a small number of microcalorimetry titrations of polyelectrolyte solutions published. Therefore we carried out potentiometric and microcalorimetric titrations of hydrochloric form of the linear and branched polyamines at 25°C and 65°C, to study the influence of the stmcture on the acid-base properties. 

The use of computer simulations to study internal motions and thermodynamic properties is receiving increased attention. One important use of the method is to provide a more fundamental understanding of the molecular information contained in various kinds of experiments on these complex systems. In the first part of this paper we review recent work in our laboratory concerned with the use of computer simulations for the interpretation of experimental probes of molecular structure and dynamics of proteins and nucleic acids. The interplay between computer simulations and three experimental techniques is emphasized (1) nuclear magnetic resonance relaxation spectroscopy, (2) refinement of macro-molecular x-ray structures, and (3) vibrational spectroscopy. The treatment of solvent effects in biopolymer simulations is a difficult problem. It is not possible to study systematically the effect of solvent conditions, e.g. added salt concentration, on biopolymer properties by means of simulations alone. In the last part of the paper we review a more analytical approach we have developed to study polyelectrolyte properties of solvated biopolymers. The results are compared with computer simulations. 

The polyelectrolyte properties of pectins are breefly exposed specially the role of the carboxylic groups distribution along the chain is demonstrated to controll the electrostatic properties. The viscometric behaviour depends on the ionic concentration and on the nature of the counterions in relation with electrostatic repulsions. 

It is the unique properties exhibited by polyelectrolytes that have led to their use in a variety of biomedical applications. Therefore, any discussion of polyelectrolytes as biomaterials should provide some insight into the properties of polyelectrolyte systems. In this section, an overview of polyelectrolyte properties will be presented, including polyelectrolyte solutions, gels, and complexes. The purpose of this section is not to provide an exhaustive review of polyelectrolyte thermodynamics but to provide background information for the ensuing discussion of biomedical applications of polyelectrolytes. 

One disadvantage of using salt solution as eluent is that the lignin sulfonates tend to adsorb onto the gel matrix, resulting in a resolution inferior to that obtained by elution with water. On the other hand, elution behavior with water is adversely affected by the polyelectrolyte properties of the lignin sulfonates. Adsorption, which is caused by the phenolic hydroxyl... 

Non-sulfonated lignins such as those from alkaline pulping processes are insoluble in water but easily soluble in sodium hydroxide solutions. When dissolved in and eluted with a sodium hydroxide solution, they show polyelectrolyte properties, i.e., the molecular species interact. As revealed by Figure 9, the fractionation result is strongly dependent on the sodium hydroxide concentration up to a concentration of 0.4M. A 0.5M sodium hydroxide solution is thus an appropriate eluent for fractionation on Sephadex G-50 (3). 

Because of the polyelectrolyte properties of lignins, elution is performed with electrolyte solutions. If the lignins are water soluble and the column... 

The free radical polymerization of DADMAC (M,) with vinyl acetate (M2) in methanol proceeds as a nonideal and nonazeotropic copolymerization with monomer reactivity ratios rx=1.95 and r2=0.35 were obtained [75]. The resulting low molar mass copolymers were reported to be water soluble over their whole range of composition. Modification of the vinyl acetate unit by hydrolysis, ace-talization, and acylation resulted in DADMAC products with changed hydrophilic or polyelectrolyte properties [75]. For the copolymerization of DADMAC and AT-methyl-AT-vinylacetamide (NMVA) a nearly ideal copolymerization behavior could be identified [45]. The application properties of the various copolymer products will be discussed in Sect. 8. 

Ephraim, J. H., Alegret, S., Mathuthu, A., Bicking, M., Malcom, R.L., and Marinsky, J. A. (1986). A unified physicochemical description of the protonationandmetal ion complex-ation equilibria of natural organic acids (humic and fulvic acids). 2. Influence of polyelectrolyte properties and functional group heterogeneity on the protonation equilibria of fulvic acid. Environ. Sci. Technol. 20, 354-366. 

Cleland, R. L., Wang, J. L., and Detweiler, D. M. (1982). Polyelectrolyte properties of sodium hyaluronate. 2. Potentiometric titration of hyaluronic acid. Macromolecules 15 386-395. 

In 1968, already back in Italy, Vittorio was called as full professor to the University of Trieste, where he founded the Macromolecular Chemistry Laboratory, leading a number of young scientists who still are active in the field of carbohydrate and polysaccharide chemistry. His main interest during this period was investigations on the polyelectrolytic properties of synthetic and natural polymers, including the very poorly studied ionic polysaccharides. 

Consideration of the dissolution of humic substances in a variety of solvents takes account of structures and some physicochemical properties of solutes and solvents. Special emphasis is given to the polyelectrolyte properties of humic substances, and to the secondary forces that must be overcome in the solvent and macromolecular systems before solution takes place. 

Li X, Reed WF. Polyelectrolyte properties of proteoglycan monomers. J Chem... 

Lyubartsev AP, Nordenskiold L. Monte Carlo simulation study of DNA polyelectrolyte properties in the presence of multivalent polyamine ions. J. Phys. Chem. 1997 101 4335. 

Kim MW, Peiffer DG. Polyelectrolyte properties of ionomeric polymers. Eu-rophys Lett 1988 5 321-326. 

The polyelectrolytic properties of chitosan may further be used to form complexes with DNA plasmid, which are protected from enzymatic degra-dation. 5 MacLaughlin et al. foxmd that plasmid-chitosan complexes with a 1 2 ionic charge ratio were stable in vitro Furthermore, they foxmd that the chitosan complexes, when containing the endosomolytic peptide GM225.1, led to transgene expression in small intestine of rabbits, while naked plasmids yielded no expression. 

PEI has typical polyelectrolyte properties it is a highly viscous hygroscopic liquid, completely miscible with water and lower alcohols, insoluble in benzene, and reactive toward cellulose. PEI is mainly used as a size, flocculating agent, or protective colloid, notably in the paper and textile industries, because of its ability to bind to cellulosic fibers. 

The primarily applications with few or no modification (other than sulfonation or hydroxymethylation) of lignin are as dispersants, emulsifiers/surfactants, binders and sequestrants. These uses represent relatively low value and limited applications, but by the development of appropriate technologies to modify, control and amplify lignin s polyelectrolyte properties, chemical reactivity and compatibility properties with other monomers and polymers, it could be turn into higher-value polymer products. 

Cohen, W. D. 1968. Polyelectrolyte properties of the isolated mitotic apparatus. Exp. Cell Res., 51 221-236. 

Poiyester dendrimers Hyperbranched aromatic polyesters based on 5-acetoxyisophthalic acid (Tg = 239 C) and 5-(2-hydroxyethoxy)isophthalic acid (Tg = 190 C) Carboxylic acid terminal groups degree of branching 50% [tj], polyelectrolyte properties discussed. [267]... 

On the other hand, copolymers of maleic acid with various vinyl monomers had been investigated in studying the influence of local charge density on polyelectrolyte properties, and some alternating copolymers of maleic acid with n-alkyl vinyl ethers were found to undergo the conformational transitions from the compact form to the extended coil upon ionization of primary carboxyl groups in maleic acid. " The hydrophobic interaction seems to be responsible for stabilization of the compact form. Viscometric, potentiometric and calorimetric measurements have been used to study the transition mechanisms. 

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