Versatility of polymers

The versatility of polymer-assisted enzymatic synthesis of non-natural and biologically significant glycolipid derivatives was also demonstrated by constructing pseudo-ganglioside GM3, see K. Yamada, S. Matsumoto, S-I. Nishimura, Chem. Commun. 1999, 507-508. 

As with silane, immobihsation of the antibody is usually performed using glutaraldehyde and deactivation of the antibody is often a problem as a result, but the versatility of polymers means that various fimctionahsed surfaces can be produced allowing antibody binding through other groups besides amines. 

Given the versatility of polymers, they can be classified according to different criteria. In this section, we review some of these classifications. 

So far, we have summarized strategies to exploit the chemical versatility of polymer brushes to either immobilize biomolecules by covalent attachment or for significantly decreasing protein adsorption. However, the extended interface created by the brush in a good solvent also provides a swellable, soft layer that can promote the nonspecific immobilization of enzymes and provide an environment that supports their activity. We have tested the functionality of enzymes physisorbed from solution [11]. Because this type of binding is weak, the conformation and activity of the proteins is expected to remain largely intact. To assess the influence of polymer brush chemistry, wettability, and swellability on the physisorption of proteins, model enzymes were chosen. Alkaline phosphatase (ALP) and horseradish peroxidase (HRP) were selected because they both catalyze the transformation of a colorless substrate to a colored product, and the enzymatic activity can therefore be easily monitored with colorimetry. The substrate of choice for ALP is /lara-nitrophenyl phosphate (pNPP), which is hydrolyzed to yield yellow /lara-nitrophenol (pNP) (Figure 4.14). 

The versatility of polymers, already commented on, must be taken to apply not only to these materials as a class, but also to many of its individual members. Poly(ethylene terephthalate) (PET), for instance, is used not only as a textile fibre but also as a packaging material in the form of both film and bottles. Poly(vinyl chloride) (PVC) is used not only as a rigid material for making mouldings but also, in plasticised form, for making flexible tubing and artificial leather. 

Polymers are found in such a large variety of products that they have shaped modern life. The extraordinary versatility of polymers in terms of end-use properties is due to the variety and complexity of the microstructure of the polymeric material. The polymeric material includes both the polymer and the additives with which it is compounded. The microstructure of the polymeric material is determined by the molecular and morphological characteristics of the polymer itself, the way in which the polymer is processed and the additives used for compounding (Figure 1.1). The molecular characteristics of the polymer include chemical composition, monomer sequence distribution (MSD), molecular weight distribution (MWD), polymer architecture, chain configuration and morphology. 

Since then, a large number of useful polymers have been developed, offering a large variety of properties and applications. This is made possible by the unique properties and structural versatility of polymers compared to other categories of materials such as ceramics and metals. The significance and utility of polymers is illustrated by the following facts. ... 

Herman was one of the first to demonstrate the versatility of polymers by developing application for acrylic polymers as oil additives, antioxidants, plasticizers, fibers, coatings and surfacants, as well as related compounds for flame retardants, foams, bactericides and pesticides. 

The past decade has witnessed an explosion of techniques used to pattern polymers on the nano- and sub-micrometre scale, driven by the extensive versatility of polymers for diverse applications such as molecular electronics, data storage, and all forms of sensors. Lyuksyutov and co-workers [349] demonstrate a novel lithography technique - electrostatic nanolithography using AFM - that generates features by mass transport of polymer within an initially uniform, planar film without chemical crosslinking, substantial polymer degradation or ablation. 

Conductive polymer composites can be defined as insulating polymer matrices which have been blended with filler particles such as carbon black, metal flakes or powders, or other conductive materials to render them conductive. Although the majority of applications of polymers in the electrical and electronic areas are based on their ability to act as electrical insulators, many cases have arisen more recently when electrical conductivity is required. These applications include the dissipation of electrical charge from rubber and plastic parts and the shielding of plastic boxes from the effects of electromagnetic waves. Consequently, materials scientists have sought to combine the versatility of polymers with the electrical properties of metals. The method currently used to increase the electrical conductivity of plastics is to fill them with conductive additives such as metallic powders, metallic fibres, carbon black and intrinsically conducting polymers such as polypyrrole. 

These two examples are typical of to what extent polymer—surfactant interactions in aqueous solution can influence the solid-liquid interface characteristics. In the present case, according to the nature of the solid surface, either the polymer or the surfactant can act as a linker to the surface for the other which has no reason to spontaneously adsorb onto it. The practical outcomes of such systems are numerous. At this stage, it is interesting to review some other studies dealing with similar systems, to illustrate the high versatility of polymer-surfactant associations as potential solid-surface modifiers. The most well-known examples are listed in Table 1. 

PoIy(vinyl chloride), PVC, is one of the most versatile of polymers, and the following forms have important applications rigid (unplasticized) grades, plasticized compounds, copolymers and blends. This is perhaps surprising since it is one of the least stable polymers, for which reason much of the early development was concerned with copolymers and with plasticized compositions. 

The development of polymer chemistry was particularly important in the last, XX centaury. New types of polymers, with different properties, were obtained. They found application as construction materials, foils, synthetic fibers, S5mthetic rubbers, adhesives, ion exchangers, products to change the soil structure, coagulating agents, in medicines, electric conductors and semiconductors, photoconductors, etc. The diversity and versatility of polymers, provided by the possible infinite modification of their molecular and macroscopic structure guarantees a further development and increase of applications of these materials. 

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