Please cite this article in press as: V.I. Petrenko, et al., On the impact of surfactant type on the structure of aqueous ferrofluids, Colloids Surf. A: Physicochem. Eng. Aspects (2017), http://dx.doi.org/10.1016/j.colsurfa.2017.03.054 ARTICLE IN PRESS G Model COLSUA-21502; No. of Pages 5 Colloids and Surfaces A: Physicochem. Eng. Aspects xxx (2017) xxx–xxx Contents lists available at ScienceDirect Colloids and Surfaces A: Physicochemical and Engineering Aspects journal homepage: www.elsevier.com/locate/colsurfa On the impact of surfactant type on the structure of aqueous ferrofluids V.I. Petrenko a,b,∗ , O.P. Artykulnyi a,b , L.A. Bulavin b,c , L. Almásy d , V.M. Garamus e , O.I. Ivankov a,c , N.A. Grigoryeva f , L. Vekas g , P. Kopcansky h , M.V. Avdeev a,f a Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna, Russia b Physics Department, Kyiv Taras Shevchenko National University, Kyiv, Ukraine c Institute for Safety Problems of Nuclear Power Plants, Chornobyl, Ukraine d Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest, Hungary e Helmholtz-Zentrum Geesthach, Geesthacht, Germany f Faculty of Physics, St. Petersburg State University, Saint Petersburg, Russia g Center for Fundamental and Advanced Technical Research, Romanian Academy-Timisoara Branch, Timisoara, Romania h Institute of Experimental Physics, Slovak Academy of Sciences, Kosice, Slovakia h i g h l i g h t s • Impact of surfactant type on ferroflu- ids structure was considered. • Magnetic nanoparticles aggregates of different size and type were observed. • Behaviour of surfactant molecules in aqueous solutions effects MFs final structure. g r a p h i c a l a b s t r a c t a r t i c l e i n f o Article history: Received 28 November 2016 Received in revised form 17 February 2017 Accepted 26 March 2017 Available online xxx Keywords: Aqueous ferrofluids Nanoparticle aggregation Sodium oleate Dodecylbenzene sulfonic acid Micelle formation Small-angle neutron scattering a b s t r a c t The impact of surfactant type on the structure organization of aqueous ferrofluids was considered based on the data of small-angle neutron scattering (SANS). The aggregates of different sizes and types were observed for magnetite magnetic nanoparticles of in heavy water stabilized by sodium oleate (SO) or dodecylbenzene sulphonic acid (DBSA). According to the surface tension measurements it was shown the significant difference of the critical micelle concentrations for SO and DBSA solutions. The observed struc- tural difference of the aggregates in the ferrofluids was related to the behaviour of surfactant molecules ∗ Correspondence to: Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, 141980 Dubna, Moscow Reg., Russia. E-mail address: vip@nf.jinr.ru (V.I. Petrenko). http://dx.doi.org/10.1016/j.colsurfa.2017.03.054 0927-7757/© 2017 Elsevier B.V. All rights reserved.