Monodispersed spheroid BaSO4 nano powders with porous structures were synthesised via a facile single step procedure. Liquid-liquid chemosynthesis involving direct precipitation of BaCl2 and (NH4)(2)SO4 in aqueous polyvinyl alcohol (PVA) solution as a polymeric template was employed. PVA, a polymeric surfactant, acts as a template for particle growth and assists morphology control and can be easily removed after synthesis by calcination. The dried and calcined nano powders were characterised by X-ray diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermo gravimetric analysis (TGA). The studies revealed that the porosity and size of the particle were highly governed by PVA content and calcination temperatures. The powder synthesised in 3% w/v PVA showed an average particle size ranging from 20 to 23 nm. The monodispersed porous powders were stable and showed spheroid like structures up to 600 degrees C; after which the nano structure is lost drastically and agglomeration leads to structure collapse forming lumpy flakes. (C) 2012 Elsevier B.V. All rights reserved.