Biomimetic Design of Chelating Interfaces

Siderophores are naturally occurring small molecules with metal binding constants greater than many synthetic chelators. Herein, we report a two-step process to graft a siderophore-mimetic metal chelating polymer from a polypropylene (PP) surface. Poly(methyl acrylate) was first grafted from the PP surface by photoinitiated graft polymerization, followed by the conversion into poly(hydroxamic acid) (PHA) to obtain PP-g-PHA films. ATR/FTIR, contact angle, SEM, and AFM were performed to characterize surface properties of films. Iron binding kinetics and the influence of pH (3.0-5.0) on the chelating ability of films were determined. PP-g-PHA exhibited significant iron chelating activity (similar to 80 nmol/cm(2)) with an equilibration time of 24 h. The materials retained 50% chelating ability at pH 3.0 compared with pH 5.0, almost double the retention of previously reported polycarboxylate chelating interfaces. By using siderophore-mimetic surface chemistry, such effective metal chelating interfaces can extend the applications of metal chelating polymers in environmental remediation, water purification, and active packaging areas. (C) 2014 Wiley Periodicals, Inc.