Photoresponsive polyacrylamide (PAA) was synthesized by grafting 4,4'-azodianiline on PAA via the Mannich reaction. The ratio of azo component can be conveniently adjusted through controlling the reaction temperature. Hydrogen bonding between the amino group on the grafted azo component and PAA main chain is utilized to amplify the photoresponse. Dynamic light scattering study showed that the average hydrodynamic size of PAA having similar to 5 mol % of azo component decreased similar to 24% after UV irradiation at 365 nm. (C) 2008 Wiley Periodicals, Inc.