Theophylline Molecular Imprinted Composite Membranes Prepared on a Ceramic Hollow Fiber Substrate

Theophylline (THO) molecular imprinted composite membranes (MIM) were successfully prepared by thermal-initiated free radical polymerization on the surface of alpha-Al2O3 ceramic microporous hollow fiber substrate membranes. Molecular imprinted polymerization layer was synthesized by taking theophylline as the template molecule, methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EDMA) as the cross-linker, and 2,2'-azobisisobutyronitrile (AIBN) as the free-radical initiator. After polymerization and the elution of the imprinted molecule, the R-max (the maximum pore size) upon the membrane surface decreased from 2.8 to 1.9 mu m. The imprinted layer upon the ceramic membranes was investigated by scanning electron microscopy (SEM), atomic force microscope (AFM) and Fourier transform infrared spectroscopy (FTIR). SEM micrographs showed a 1 mu m thick composite membrane, and AFM showed different surface roughness. Moreover, the selectivity separation factor of theophylline (THO) to theobromine (TB) was determined as 2.63 in a mixed feed solution, thus suggesting that the imprinting process allowed for preferential permeance and affinity selectivity to THO.