Hierarchical In2O3 rod-like microbundles were fabricated via the Pluronic F127-(EO106PO70EO106-) assisted hydrothermal reaction followed by calcining the In(OH)(3) precursors. The results revealed that the In2O3 microarchitectures were constructed with well-aligned one-dimensional (1D) single-crystalline nanorods with highly uniform morphologies and particular exposed facets. Structural analysis suggested that the In2O3 nanorods were enclosed by {1 1 0} and {0 0 1} facets. The triblock copolymer acted as a structure-directing agent and played a key role in the formation of In(OH)(3) microbundles. The formation of the precursors In(OH)(3) microbundles was studied through contrastive experiments and computational simulation, which can be contributed to the soft-template-directed self-assembly mechanism. The gas sensing properties of the as-prepared In2O3 microbundles were investigated. Compared to the samples prepared in the absence of F127, the In2O3 microbundles exhibited a superior sensing performance toward 2-chloroethanol vapor, which can be explained by hierarchically ordered structures and exposed crystal surfaces. (C) 2010 Elsevier Inc. All rights reserved.