The effect of addition of salt potassium chloride (KCl) and detergent sodium dodecyl sulfate (SDS) on the aqueous solution of PEO‐PPO‐PEO (polyethylene oxide‐polypropylene oxide‐polyethylene oxide) tri‐block copolymer, i.e. $(\mathrm{EO}{)}_{103}(\mathrm{PO}{)}_{39}(\mathrm{EO}{)}_{103}$ Pluronics F88 has been carried out. The concentration of F88 was fixed at 5 wt‐% and the concentrations of KCl and SDS were varying in the range of 0.05 to 1.5 M and 0.001 to 0.125 M, respectively. Small‐angle neutron scattering (SANS) experiments were carried out using 36 m SANS spectrometer at Neutron Scattering Laboratory, Serpong (SMARTer), Indonesia. The wavelength of neutron beam was 3.90 Å and the experiments were performed at two different sample‐to‐detector distances of 2 m and 8 m. A ${}^3\mathrm{He}$ of 128×128 two‐dimensional position sensitive detector (2D‐PSD) with a beam stopper of 60 mm in diameter was used to detect the scattered beam in the range of ${\text{0.008<Q(Å}}^{\text{−1}}\text{)<0.25.}$ All measurements were performed at room temperature. It is observed that increasing the concentration of the above additives induced the micellization of block copolymers to form a core‐shell micelle structure.