Pluronics are series of closely related block copolymers of ethylene oxide and propylene oxide and are used primarily in pharmaceutical formulation as emulsifying or solubilizing agents.  In this study, the crit. micelle concn. (CMC) of different pluronics such as L61, L62, L63, L64, L92, F38, and F68 was measured by two different methods.  The first method is the surface tension method (ring method)​; the second one is fluorimetrical method by using DPH (1,​6 di-​Ph hexatriene)​.  It was found that, by increasing the lipophilicity of the block copolymer (increase the propylene oxide moiety) the CMC value increases.  Also, the fluorimetric method is very sensitive, accurate and more reproducible than surface tension method.