COLL 243 |
| Husam Jumaa and Joseph B. Schlenoff. Department of Chemistry and Biochemistry, Florida State University, Dittmer Building, Analytical Division, Tallahassee, FL 32306 |
| The concept of layer-by-layer deposition of polyelectrolytes to form multilayers can be further employed to synthesize catalytically active thin films. By the use of imidazole containing multilayers one can catalyze the hydrolysis of esters, such as p-nitrophenylacetate, which is a model for the catalysis of a-chemotrypsin. 4-(5)vinylimidazole was utilized to synthesize various poly(vinylimidazoles) which were subsequently partially quaternized. Copolymers containing an acrylic acid moiety were also made. The synthesized polymers were characterized by infrared spectroscopy ellipsometerly, as well as other means. These polyelectrolytes where then utilized in different multilayer systems to evaluate the catalytic activity of viniylimidazole multilayers under different conditions. Different multilayers included poly(vinylimidazoles) with different degrees of quaternization, since it should be expected that the higher the quaternization, the lower the catalytic effect. Polyelectrolytes were used that contain a carboxyl group moiety adjacent to the nitrogen of the imidazole, which is believed to induce higher catalytic activity. Different salts were used at different concentrations in an attempt to control permeability of the multilayer. The hydrolysis of p-nitrophenylacetate was monitored at 400nm, which is the absorbance wavelength for p-nitrophenoxide ion, and plots of absorbance vs. time were recorded for the different multilayer systems. Comparisons of homogeneous solution vs. heterogeneous multilayer catalysis were made. |
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Fundamental Research in Colloid and Surface Chemistry
Division of Colloid and Surface Chemistry |