Polymer precomplexed

PVP may react with dichlorobis(2,2 -bipyridyl)ruthenium(II) and the precomplexed polymer may then be used to dip coat various electrodes.52 EDTA complexes of ruthenium(III) will react with PVP and may thereby be immobilized on electrodes. The use of transparent graphite electrodes facilitates the spectroscopic monitoring of both the quantity of PVP and ruthenium on the electrode. Also the Ru111 -+ Ru11 reduction may be followed as it proceeds. The UV spectra of the immobilized EDTA complexes are similar to those in solution. It has been possible to use a band... 

The transport of charge by electron hopping is an attractive model for these systems. In the case mentioned above, the electrode response is better from the precomplexed polymer film than from one prepared by first coating with PVP, then dipping into a solution containing a source of [Fe(CN)5(H20)] thus the spatial distribution of redox centres is important as well as their number in determining electrode response. Data for the pentacyanoferrate system support charge transport via adjacent redox sites and the rate of this transport falls off rapidly below a critical concentration of centres. ... 

Precomplexation is not as effective in a homogeneous system, where the complexing agent has an opportunity to diffuse away from the polymer and complex with the acceptor monomer. This is particularly true when precomplexation time is short (Table XVI). 

Table XVII shows the grafting of poly (styrene-alt-acrylonitrile) on nitrile rubber precomplexed with EASC. This system is heterogeneous since addition of EASC to the polymer solution causes the polymer to agglomerate or precipitate.

Moreover, efficiency of phase inversion imprinting can be improved with pre-forming complex of monomer-template (Table 2) in copolymerization [70]. The THO-acrylic acid or methacrylic acid precomplex monomer was copolymerized with acrylonitrile in DMSO. The resultant viscous solution contents were used for phase inversion in water after template copolymerization. Template copolymers can improve binding capacity of THO. From H-NMR analysis, this is due to tailor-made modification of a copolymer backbone for the template molecule. Also, comparison was made between copolymers of acrylic acid and methacrylic acid in THO selectivity of the imprinted polymers. Presence of the methacryl methyl group is more efficient in the tailor-made structure of the THO template. 

While most copolymers of vinyl acetate are random copolymers, alternating copolymers are formed when the reactivity ratios for the two monomers are suitable. This occurs spontaneously when vinyl acetate is polymerized with electron-poor monomers such as maleic anhydride [273]. Alternatively, it has been reported that acrylonitrile which has been precomplexed with zinc chloride gives alternating polymers with vinyl acetate [274]. Block polymers of vinyl acetate with methyl methacrylate, acrylonitrile, acrylic acid, and n-vinyl pyrrolidone have been prepared by the strategy of preparing poly(vinyl acetate) macroradicals in poor solvents in which the macroradicals are occluded. Addition of a second monomer swells the polymer coils, and polymerization continues with the addition of the new monomer [275]. 

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