Poly , interaction with metal ions

Binding behavior of transition metal ions with polyallylamine20), poly(e-A-methacryloyl-L-lysine)2,), branched poly(ethyleneimine)s 22), water soluble polymer-bound iminodiacetic acid analogue 23), and polyacrylamide gel 241 has been reported. In these works, the effect of the polymer backbone has been discussed in terms of interaction of metal ions with the polymer chains. 

W. Szer Interaction of Poly r-T with metal ions and aliphatic amines. 

Water soluble cetylpyridinium chloride modified poly(ethyleneimine) 13 were investigated for the removal of several cations (Cu ", Zn , Cd , Pb ", etc.) and anions (POi CrOl") from water [113]. The polymer can form interaction products with negative ions due to electrostatic bonds and also with metal ions due to complex formation. Other basic polymers such as poly(vinylamine), neutral polymers such as polyalcohols and acidic polymers sueh as poly(aerylic acid) were investigated using the method of Liquid-Phase Polymer-Based Retention for the separation of metal ions from aqueous solution [114]. 

It has been demonstrated that dendrimers can be used also as fluorescent sensors for metal ions. Poly(propylene amine) dendrimers functionalized with dansyl units at the periphery like 34 can coordinate metal ions by the aliphatic amine units contained in the interior of the dendrimer [80]. The advantage of a dendrimer for this kind of application is related to the fact that a single analyte can interact with a great number of fluorescent units, which results in signal amplification. For example, when a Co ion enters dendrimer 34, the fluorescence of all the 32 dansyl units is quenched with a 32-fold increase in sensitivity with respect to a normal dansyl sensor. This concept is illustrated in Fig. 3. 

SN)X can act as an efficient barrier electrode in ZnS junctions, increasing the quantum efficiency of the blue emission by a factor of 100 over gold.14 It can also be used to increase the efficiency of GaAs solar cells by up to 35%. Metal ions interact more strongly with a poly(sulfur nitride) surface than with other metal electrodes. This property has stimulated investigations of possible applications of (SN)X as an electrode material. 

The interaction of poly(ethylene oxide) and other polar polymers with metal salts has been known for many years (Bailey and Koleska, 1976). Fenton, Parker and Wright (1973) reported that alkali metal salts form crystalline complexes with poly(ethylene oxide) and a few years later, Wright (1975) reported that these materials exhibit significant ionic conductivity. Armand, Chabagno and Duclot (1978, 1979) recognised the potential of these materials in electro-chemical devices and this prompted them to perform more detailed electrical characterisation. These reports kindled research on the fundamentals of ion transport in polymers and detailed studies of the applications of polymer-salt complexes in a wide variety of devices. 

Besides some conventional supports, a new carrier material, poly-alumazane, was tested. Poly-alumazane, which was recently reported by Chinese researchers8, is a silica carrier, the surface of which is modified by subsequent treatments with aluminum chloride and ammonia, forming an Al-N phase on the silica surface. This coating is able to interact with two-valent noble metal ions (like Pd11) which is found to result -after reduction- in a catalyst with very high dispersion. 

Interaction of bivalent metal cations with poly(glutamic acid) has been extensively investigated 6-17), including the induction of a-helix formation by transition metal ions. Nevertheless, available data are not sufficient to explain the wide variety of metal-ion-induced conformational changes. 

Complexation of poly(allylamine hydrochloride), — (CH—(CH2NH3C1)—CH2) —, with transition metal ions in aqueous solution appears to proceed in one step, in contrast to that of the corresponding low molecular weight metal complex. Interaction between polyallylamine and Cu2+, Ni2 +, Co2+, Zn2+, and Mg2+ has been reported 21). 

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