An approach to nanoparticles based upon the thermosensitivity of a copolyether is described Two thermosensitive copolymers of glycidol with molar masses of 800,000 g/mol randomly substituted with ethyl isocyanate (28 and 35% substitution) were used to obtain mesoglobules The effects of copolymer concentration and of the presence of surfactants (sodium dodecyl sulfate and hexadecyltrimethylammonium bromide) on the size of the mesoglobules formed were investigated The obtained mesoglobules were monomodal and of narrowly distributed diameters, as shown by dynamic light scattering and atomic force microscopy measurements The radical nucleated copolymerization of N-isopropylacrylamide with N,N'-methylenebisacrylamide as a crosslinker was performed in the presence of the mesoglobules Nanoparticles of monomodal size distribution and low dispersity were obtained (C) 2010 Wiley Periodicals, Inc J Polym Sci Part A Polym Chem 48 4074-4083, 2010