Superabsorbent polymer particles, consisting of partly neutralized, slightly crosslinked poly(acrylic acid), have been surface-crosslinked photochemically. Surface crosslinking is required for many applications of superabsorbent polymers, such as disposable diapers, to control the flow and absorption of liquids in the gel bed. Photoinduced surface crosslinking has been achieved under UV irradiation (200-300 nm) with (NH4)(2)S2O8 as a photoactivated crosslinking agent. In comparison with the currently used thermal ester bridging method for surface crosslinking, the new photochemical method generates superabsorbent particles with Superior properties, such as an improved flow of liquid through the get bed, which utilizes the entire gel bed. These improved properties have been shown by water absorption capacity studies, fluid flow dynamics, environmental scanning electron microscopy, and low-energy ion-scattering Studies. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 2163-2170, 2009