Here we report comprehensive analysis on the influence of different alkyltriphenyl phosphonium (CnTPPBr) (with varying alkyl chain lengths) based cationic surfactants displaying analogical characteristics to ionic liquids (IL) on the physicochemical properties of an ethylene oxide–propylene oxide (EO–PO) triblock copolymer, Pluronic®, P103 (EO17-PO60-EO17; M. Wt-3250) using several techniques viz. cloud point (CP), viscosity, small angle neutron scattering (SANS), dynamic light scattering (DLS) and high sensitivity differential scanning calorimetry (HSDSC). The CP results indicate notable increase in values with the increase in alkyl chain length of IL. A significant decrease in the micelle size was witnessed from the DLS and SANS results. The presence of sodium bromide (NaBr), however, counteracted the disruptive effect of ILs and promoted micellar growth. The critical micelle temperature (CMT) results attained using HSDSC are also reported. The information acquired from the present study will be highly beneficial in understanding the behavior of Pluronic® micelles in the presence of CnTPPBr ILs and for their effective utilization in various industrial applications.