Shear rate was utilized for the morphology-controlled synthesis of silver nanoparticle decorated poly(o-phenylenediamine) (AgNPs-PoPD) using microfluidics. The morphology of AgNPs-PoPD, such as bundles of belts, twisted fibers, clusters, and microspheres, as well as the composition of AgNPs-PoPD clusters can be easily controlled by changing shear rates, which may provide a new potential method for the property control of materials. The phase diagram of AgNPs-PoPD morphology against reactant flow rate was obtained. The formation mechanism of different morphology of AgNPs-PoPD were analyzed and discussed based on numerical simulations. A H2O2 sensor based on AgNPs-PoPD spheres was fabricated, due to its good catalytic activity toward the reduction of H2O2. The linear detection range is determined to be from 20 mu M to 180 mu M, with the detection limit of 5.7 mu M at a signal-to-noise ratio of 3. (C) 2015 Elsevier B.V. All rights reserved.