A combined theoretical study, density functional theory (DFT) and dissipative particle dynamics (DPD) method, was performed to investigate intrinsic mechanism for self-assembly of poly(styrene)-blockpoly(4-vinylpyridine) (PS-b-P4VP) and poly(4,4'-oxydiphenylenepyromellitamic acid) (POAA) blends in both microscopic and mesoscopic scales. The geometric structures, bonding energies and infrared (IR) spectra for the potential hydrogen bonding in the blends were obtained using the Becke-three Lee-Yang-Parr (B3LYP) method, and the morphologies for different blends were investigated by DPD simulations. From the quantum-chemical calculations, the hydrogen bonding between P4VP and POAA chains, and among POAA chains are confirmed. Due to different bonding strength, competitive hydrogen bonding is caused, the hydrogen bonding brought by POAA governs the morphology evolution, from lamellar to sphere. This report provides good understanding for the formation of morphology involved with competitive hydrogen-bonding interactions. (c) 2012 Elsevier Ltd. All rights reserved.