Amphiphilic pentablock copolymer (CBABC-type) based on poly(propylene oxide), poly(methyl methacrylate) and poly(acrylic acid) has been synthesized through ring opening polymerization (ROP) and reversible addition-fragmentation chain transfer polymerization (RAFT) techniques. Gel permeation chromatography (GPC) results envisage the control nature of polymerization. Structural property and thermal behavior of the pentablock copolymer have been analyzed through various characterization techniques. Further, a novel nanocomposite comprised of iron oxide nanoparticles (Fe3O4 NPs) and penta block copolymer has been successfully developed and characterized using various techniques. Vibrating Sample Magnetometer (VSM) results indicate that the presence of copolymer has no adverse effect towards the magnetic property of Fe3O4 NPs. Comparative studies towards micellar stability and pH-triggered release behavior of pentablock copolymer and nanocomposite have been discussed in detail. (C) 2017 Elsevier Ltd. All rights reserved.