Kinetics of interfacial radical polymerization initiated by a glucose-oxidase mediated redox system.
The reaction and coating kinetics for the glucose oxidase initiated interfacial polymerization are elaborated. The interfacial film grows rapidly and linearly with time, producing time-dependent controllable conformal coating thicknesses of up to a millimeter in less than 4 min. Bulk polymerization was only observed when the immersing media was stirred to induce higher mass transport rates. The dramatically different film thicknesses observed between different concentrations of glucose in the hydrogel and iron in the bulk media are demonstrated to be a result of an initial rapid growth phase following which the film grows at the same rate nearly independent of either the glucose or iron concentration. The polymerization rate and hence the thickness growth rate in this initial phase saturate at glucose and iron concentrations above 0.8 M and 0.63 mM, respectively. At iron concentrations above 0.05 mM, the film thickness at the end of 3 h of reaction monotonically decreased with increasing iron concentration from 5.7 mm to 4.2 mm. The glucose oxidase is trapped by the growing polymerization front and can be used as the sole enzymatic precursor to coat a second polymeric layer. However, the rate of film growth of the second layer is 14-fold lower than the rate of film growth when bulk enzyme is present during the second stage coating process.
Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80309, USA.
Raveesh
R
Shenoy
Christopher N
CN
Bowman
D001234:Aspergillus niger / Q000378:metabolism; D001672:Biocompatible Materials / Q000737:chemistry*; D005609:Free Radicals; D005947:Glucose / Q000737:chemistry; D005949:Glucose Oxidase / Q000737:chemistry*; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D008422:Materials Testing; D010084:Oxidation-Reduction; D058105:Polymerization; D011108:Polymers / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors
D001672:Biocompatible Materials; D005609:Free Radicals; D020100:Hydrogels; D011108:Polymers; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D007501:Iron; D005949:Glucose Oxidase; D005947:Glucose