The increasing demand for the heat transfer intensification in microelectronics, high-tech industries or even in transportation motivates the search for new solutions in this field of science. One of the studied concepts is the application of nanofluids characterized by enhanced thermal properties, e.g. improved thermal conductivity or overall heat transfer coefficient. In this work a simple synthesis method of temperature responsive CuO-water colloidal system is presented. In the experiments a two step synthesis method was employed and several different copolymers of poly(N-isopropylacrylamide) were used as stabilization agents. The main efforts of the research were focused on the obtaining of colloidal system which stability would suddenly collapse at desired chosen temperature. Additionally, such transition should be reversible. The synthesized samples were characterized by particle size distribution analysis, zeta potential, absorbance and thermal conductivity. It was proved that it is possible to achieve the chosen goal using appropriate combination of ultrasonication, polymer adsorption and the change of ionic strength of the mother liquid. (C) 2016 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.