Dissolved ionic species, conducting media

One of the considerations vdiich has driven the search for new synthetic parameters for the production of conducting polymer films is the need for a medium that will dissolve both the monomer to be used and polar molecules or ionic species to be incorporated into the polymer. In the case of protein incorporation, it is also important that the conditions for polymer production not denature the protein. 

Ionic conduction is the conductive migration of dissolved ions in the applied electromagnetic field. This ion migration is a flow of current that results in PR losses (heat production) due to resistance to ion flow. All ions in a solution contribute to the conduction processes however, the fraction of current carried by any given species is determined by its relative concentration and its inherent mobility in the medium. Therefore, the losses due to ionic migration depend on the size, charge and conductivity of the dissolved ions, and are subject to the effects of ion interaction with the solvent molecules [18]. 

AMPS is a water-soluble monomer it is also soluble in polar organic solvents such as methanol, dimethyl formamide (DMF), and dimethyl sulfoxide (DMSO). MPDMA is soluble in similar polar solvents. Because of the solubility characteristics of these two species, the reactions (that is, the formation of the ion pairs) were conducted in water, methanol, or DMF. The product, MPDMA AMPS, was very hygroscopic and apparently had a tendency to polymerize spontaneously during the course of isolation (solvent stripping and precipitation by non-solvents). The preferred medium for preparation was found to be anhydrous THF which also had been used for other ionic monomer pairs (13). In addition, a slight excess of MPDMA was used to ensure complete reaction of AMPS. The excess base, MPDMA, was removed using cold THF (which did not dissolve the product). 

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