Functionalized membranes by layer-by-layer assembly of polyelectrolytes and in situ polymerization of acrylic acid for applications in enzymatic catalysis

This research work was directed toward the development of highly active, stable, and reusable functionalized polymeric membrane domains for enzymatic catalysis. Functionalized membranes were created by two different approaches. In the first approach, which involved alternative attachment of cationic and anionic polyelectrolytes, functionalization was performed using a layer-by-layer (LBL) assembly technique within a nylon-based microfiltration (MF) membrane. In the second approach, a hydrophobic polyvinylidene fluoride (PVDF) MF membrane was functionalized by the in situ polymerization of acrylic acid. The enzyme, glucose oxidase (GOX), was then electrostatically immobilized inside the functionalized membrane domains to study the catalytic oxidation of glucose to gluconic acid and H₂O₂. Characterization of the functionalized membranes, in terms of polyelectrolyte/polymer domains and permeate flux, was also conducted. The kinetics of H₂O₂ formation was discussed, along with the effects of residence time and pH on the activity of GOX. The stability and reusability of the electrostatically immobilized enzymatic system were also investigated.