On polystyrene–block polyisoprene–block polystyrene filled with carbon-coated Ni nanoparticles Yunlong Jin 1 , Shah Valloppilly 1 , Dorina Magdalena Chipara 2 , Ralph Skomski 1 , Mircea Chipara 2, * , Wenyong Zhang 1 , and David J. Sellmyer 1 1 Nebraska Center for Materials and Nanoscience, The University of Nebraska, Lincoln, NE 68588, USA 2 Department of Physics, The University of Texas Rio Grande Valley, 1201 W. University Drive, Edinburg, TX 78539, USA Received: 18 September 2016 Accepted: 26 October 2016 Published online: 4 November 2016 Ó Springer Science+Business Media New York 2016 ABSTRACT The manuscript focuses on the dispersion of magnetic nanoparticles within self- assembling block copolymers, on the preferential localization of nanoparticles and on the effect of their concentration on the magnetic properties of the nanocomposites and on the self-assembly features of the matrix. Carbon-coated nickel nanoparticles dispersed within polystyrene–block polyisoprene–block polystyrene have been investigated by Raman, X-ray, SQUID, differential scanning calorimetry, and electron microscopy. The effect of nanofiller on the self-assembly features of the block copolymer is reported. Preferential local- ization of nanofiller within the soft phase was noticed below 20 wt% nanofiller. Higher loadings with nanoparticles showed an uniform distribution of nano- filler within the block copolymer, consistent with the destruction of self- assembly. The effect of nanoparticles’ concentration on blocking temperature is discussed. Introduction Recent attention is focused on elastic materials with magnetic features for rheological applications [1], electronics [2], energy [3], data storage [4], and future spintronics [5]. Medical applications [6] are exploit- ing either the magnetic characteristics for controlled localization and release of drugs or superparamag- netic features for contrast agents in Nuclear Magnetic Resonance Imaging. Block copolymers (BC) such as polystyrene–block polyisoprene–block polystyrene (PS–bPI–bPS) are attractive matrices, with excellent mechanical properties and rich morphologies derived from their self-assembly capabilities. Dispersion of magnetic nanoparticles (MNs) within BC is expected to result in nanocomposites that combine the mag- netic characteristics with the elastic features of the matrix [7]. The ability of BC to spontaneously reor- ganize in ordered structures at submicron scale opens the possibility of new nanomaterials, where the MNs are preferentially localized within a given phase of BC [8]. Preliminary data revealed that barium ferrite MNs are preferentially trapped within the soft domains (polyisoprene; PI) [7, 8], of PS–bPI–bPS. Bulk Ni is a ferromagnet with Curie temperature (T C ) of 631 K, whose nanoparticle oxidizes easily in Address correspondence to E-mail: mircea.chipara@utrgv.edu; chipara@yahoo.com DOI 10.1007/s10853-016-0539-7 J Mater Sci (2017) 52:2452–2459