Effects of interplay of nanoparticles, surfactants and base fluid on the surface tension of nanocolloids A. R. Harikrishnan, Purbarun Dhar, Prabhat K. Agnihotri, Sateesh Gedupudi and Sarit K. Das Eur. Phys. J. E, 40 5 (2017) 53 Published online: 05 May 2017 DOI: 10.1140/epje/i2017-11541-5