Communication Macromolecular Rapid Communications Macromol. Rapid Commun. 2012, 33, 218−224 © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim wileyonlinelibrary.com 218 DOI: 10.1002/marc.201100638 1. Introduction Functional nanoparticles have attracted considerable interests because of their intriguing physical properties and promising applications in devices. [1] Over the past two decades, a great amount of methods have been developed to synthesize nanoparticles with controlled morphology and small size polydispersity. [2] Despite the great success in nanoparticle synthesis, it has been found that the perform- ance of many devices are based not on the individual nano- particle itself, but rather on the superstructures assembled by the nanoparticles. Therefore, the focus on nanostruc- tured materials research has been gradually shifted from individual nanoparticle synthesis to direct nanoparticle assembly into large ordered superstructures. [1d,e,3] By tuning internanoparticle interactions or applying external force on nanoparticles (electric field, magnetic field, etc), individual nanoparticles can be assembled into ordered superstructures. [1d,3,4] To truly exploit the nanoparticle-based superstructures in devices, the nano- particle assembly has to be facile, low cost, up-scale pos- sible, and homogeneous over large area of substrates. [5] However, despite the outstanding examples of nanopar- ticle assembly demonstrated by the methods mentioned A facile route to reassemble titania nanoparticles within the titania-block copolymer com- posite films has been developed. The titania nanoparticles templated by the amphiphilic block copolymer of poly(styrene)-block-poly (ethylene oxide) (PS- b-PEO) were frozen in the continuous PS matrix. Upon UV exposure, the PS matrix was partially degraded, allowing the titania nanoparticles to rearrange into chain-like networks exhibiting a closer packing. The local structures of the Titania chain-like networks were investigated by both AFM and SEM; the lateral structures and vertical structures of the films were studied by GISAXS and X-ray reflectivity respectively. Both the image analysis and X-ray scattering characterization prove the reassembly of the titania nanoparti- cles after UV exposure. The mechanism of the nanoparticle assembly is discussed. A Facile Route to Reassemble Titania Nanoparticles Into Ordered Chain-like Networks on Substrate Ya-Jun Cheng,* Markus Wolkenhauer, Gina-Gabriela Bumbu, Jochen S. Gutmann* Prof. Dr. Y.-J. Cheng Polymer and Composites Division, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, 519 Zhuangshi Rd, Zhenhai District, Ningbo, Zhejiang Province, 315201, P. R. China; Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128, Mainz, Germany E-mail: chengyj@nimte.ac.cn Dr. M. Wolkenhauer Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128, Mainz, Germany Dr. G.-G. Bumbu Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128, Mainz, Germany Prof. Dr. J. S. Gutmann Department of Chemistry and Center for Nanointegration Duisburg- Essen (CeNIDE), University of Duisburg-Essen, Campus Essen, D-45117 Essen, Germany; Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128, Mainz, Germany; Institute for Physical Chemistry, Johannes Gutenberg University, Welder Weg 11, D-55099 Mainz, Germany Email: jochen.gutmann@uni-due.de