Polysaccharides aqueous environment

Amylose consists of unbranched al 4-linked chains of 200-300 glucose residues. Due the a configuration at C-1, these chains form a helix with 6-8 residues per turn (1). The blue coloring that soluble starch takes on when iodine is added (the iodine-starch reaction ) is caused by the presence of these helices—the iodine atoms form chains inside the amylose helix, and in this largely non-aqueous environment take on a deep blue color. Highly branched polysaccharides turn brown or reddishbrown in the presence of iodine. 

The polymer most commonly used to prepare brushes is poly (ethylene oxide) (PEO), which is alternatively called poly (ethylene glycol)(PEG). This is primarily because in an aqueous environment PEO molecules are highly mobile22 and strongly hydrated, attaining large exclusion volumes.23 Furthermore, PEO is biocompatible.24 Sometimes the role of polysaccharides to prevent bioadhesion is reported.25... 

Polysaccharides in aqueous environments may spontaneously assemble into hydrogels. These polymer gels can then penetrate neighboring gels, and anneal them together, increasing the size spectrum. Recent discoveries have highlighted... 

Nanoparticles have been prepared from polysaccharides, proteins, and amphiphilic macromolecules by inducing their aggregation followed by stabilization either by heat denaturation or chemical cross-linking. The former can be done by water-in-oil emulsion system or in aqueous environments. The cross-... 

Although the basic qualities of polysaccharides are determined by the chemical functionality of the glycosyl residues constituting the polymers, there is another specifically polymer-related dominating property a non-negligible excluded volume effect. Polysaccharides occupy volume in particular, in aqueous environment, they transform rather large compartments into functional phase spaces. At the molecular level, this performance is controlled by many parameters, in particular, the following ... 

Many liquid detergent products contain components that serve as product viscosity modifiers, added to achieve the desired consistency of the commercial product. Cellulosic polymers, for instance, are an excellent example of such an additive and various polysaccharides are capable of gelation under specific thermal conditions. In such cases, heat transfer during manufacture may be required to complete hydration and effect the necessary conformational change in the select polymer system [85], in the appropriate aqueous environment. Products requiring controlled heat transfer processes may include various dental creams, shampoos, built liquid detergents, and hard surface cleaners. 

The biosynthesis of polysaccharides is not a straightforward reversal of the hydrolysis process, because the direct polycondensation of monosugars in an aqueous environment produces a positive Gibbs energy. Instead, biosynthesis occurs when a monosugar joins onto the nonreducing end of what is called a primej ... 

Ionic polymers (polyelectrolytes and polyampholytes) constitute an important class of water-soluble maaomole-cules. ° Their monomer units are capable of ionization in polar solvents, for example, in water. The ionization occurs via either dissociation of hydrogen ions H from the acidic groups or dissociation of water molecules and protonation of the basic groups on the polymer chain. The solubility of polyelectrolytes in polar solvents is determined first of all by a huge gain in translational entropy of the counterions. The majority of bio-maaomolecules (proteins, nucleic acids, and polysaccharides) operating in aqueous environment carry ionizable groups (carboxyl, sulfate, amine, etc.) and are included in this class of polymers. 

Life in an aqueous environment can be treated at three levels. We first of all have the so-called water structure which arises from the peculiar intermolecular nature of water and which is perturbed by pressure, temperature and solutes. At the molecular level, we must examine discrete water molecules in protein crystals or in polysaccharides to see how they act in stabilizing or destabilizing certain structures. Then we have, on a more macroscopic level, water as a transport medium that distributes nutrients and carries waste products away this is a fascinating study in itself. Then, finally, there is water as the physical environment for many living organisms in oceans, rivers and lakes. Many organisms live all their lives in water, and the physical properties of water have really shaped the development of such organisms in no small amount. 

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