Densely grafted star- and comb-shaped molecular brushes composed of poly[2-(dimethylamino)ethyl methacrylate] were prepared via atom transfer radical polymerization (ATRP) using either cyclotriphosphazenes or polyphosphazenes as initiators. The grafting conditions were optimized in order to obtain well controlled brush structures. The kinetics of the reactions were first-order with respect to the monomer concentration in both cyclotriphosphazene and polyphosphazene systems. The resultant star- and comb-shaped brushes were quaternized with iodomethane, iodobutane, iodoheptane, iododecane and iodododecane. Electrospinning of the quaternized brushes gave rise to microfibers with diameters in the range of 700 nm to 1.1 �m, evidenced by scanning electron microscopy (SEM). The antibacterial activity against Escherichia coli (E. coli) of the quaternized brush species in both aqueous solution and as fibrous solids has been evaluated. In aqueous solution, star-shaped brushes quaternized with iodoheptane showed the best antibacterial effect, with a minimum inhibitory concentration (MIC) as low as 6 mg/mL. In the fibrous solid state, more than 99% of E. coli were killed within 2 hr after contacting 100 mg of microfibers electrospun from the star-shaped brush polymers quaternized with either iododecane or iodododecane.

Preparation of quaternized electrospun fibers from polyphosphazene brush copolymers and their antibacterial properties

244th National Meeting (2012)

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