Thermochromic composites constitute a classical subfamily of stimuli responsive materials. We report here the thermochromic effect in Pluronic F-127 (F127) micelles containing hydrophobic ion-exchanger and H+ chromoionophores. The highly versatile and reversible thermochromism is attributed to the temperature-induced hydration dehydration of the peripheral layer of the micelles, which in turn controls the ion-exchange process between the core and the periphery of the micelles. The color typically changes abruptly within 35 degrees C, and the color transition temperature can be tuned within 5-25 degrees C upon varying the F127 concentrations. This work lays the foundation of a new variety of thermochromic materials involving ion-exchange.