Synthesis of pH-responsive crosslinked poly[styrene-co-(maleic sodium anhydride)] and cellulose composite hydrogel nanofibers by electrospinning

BACKGROUND: Stimuli-sensitive materials show enormous potential in the development of drug delivery systems. But the low response rate of most stimuli-sensitive materials limits their wider application. We propose that electrospinning, a technique for the preparation of ultrafine fibrous materials with ultrafine diameters, maybe used to prepare materials with a fast response to stimuli. RESULTS: Poly[styrene-co-(maleic sodium anhydride)] and cellulose (SMA-Na/cellulose) hydrogel nanofibers were prepared through hydrolysis of precursor electrospun poly[styrene-co-(maleic anhydride)]/cellulose acetate (SMA/CA) nanofibers. In the presence of diethylene glycol, the SMA/CA composite nanofibers were crosslinked by esterification at 145 degrees C, and then hydrolyzed to yield crosslinked SMA-Na/cellulose hydrogel nanofibers. These nanofibers showed better mechanical strengths and were pH responsive. Their water swelling ratio showed a characteristic two-step increase at pH = 5.0 and 8.2, with the water swelling ratio reaching a maximum of 27.6 g g(-1) at pH = 9.1. CONCLUSION: The crosslinked SMA-Na hydrogel nanofibers supported on cellulose showed improved dimensional stability upon immersion in aqueous solutions. They were pH responsive. This new type of hydrogel nanofiber is a potential material for biomedical applications. (C) 2009 Society of Chemical Industry