Synthesis, characterization of naphthalene‐based polyimides, and their use as immobilized enzyme membrane

A new monomer, 1,5‐bis( p ‐dimethylaminophenylimino)naphthalene, was prepared through Schiff‐base condensation reaction of 1,5‐diaminonaphthalene and 4‐(dimethylamino)benzaldehyde in the presence of ethanol. A series of aromatic polyimides bearing naphthalene and CHN groups were synthesized from the diamine with five kinds of commercial dianhydrides via a conventional one‐stage process. The resulting naphthalene based polyimides (NBPs) showed good solubilities in N ‐methyl‐2‐pyrrolidone and m‐ cresol. NBPs had glass‐transition temperatures at 139–174°C and 10% weightloss temperatures above 430 °C in nitrogen atmospheres. Excellent properties of NBPs are attributed to the incorporation of the naphthalene and CHN group in 1,5‐bis( p ‐dimethylaminophenylimino)naphthalene. Moreover, chemically prepared polyimides were used for immobilization of glucose oxidase (GOx). The amperometric responses of the NBPs‐GOx‐Pt electrodes toward glucose were examined at a potential of 0.7 V in PBS solution by means of time‐base (TB) technique. Results show that NBPs bearing O group membrane (PI‐3) has many advantages in the immobilization of glucose oxidase because of its strong adherence to electrode surface and chemical stability and selectivity. Copyright © 2010 John Wiley & Sons, Ltd.