Synthesis and ion-binding properties of polymeric pseudocrown ethers. III.Ion-binding studies

An ion-induced templatization strategy was used to prepare crosslinked poly meric pseudocrown ethers (PCEs) in situ during a one-step free-radical poly merization. These studies bring to a conclusion the fundamental studies on the templatization process reported in the first two papers of this series. For the PCEs, with nickel as the templating ion and hydroxyethyl methacryl ate as the monovinyl comonomer, the ion-binding studies revealed a signific ant enhancement in the ion-binding capacity associated with the inclusion o f the template ion during synthesis. For example, a PCE synthesized with a monomer-to-solvent ratio of 20/80 exhibited an ion-binding capacity that wa s 7.5 times higher than a control polymer produced under identical conditio ns except for the absence of the template cations. A PCE synthesized with a monomer-to-solvent ratio of 20/80 exhibited a capacity of 0.3 mg/g polymer for Ni2+ cations. Finally, it was observed that the column could be fully regenerated by elution with a small volume of a 1 M HCl solution at 60 degr ees C, resulting in the recovery of the bound ions as a concentrated soluti on.