Preparation of positively charged oil/water nano-emulsions with a sub-PIT method

► Positively charged O/W nano-emulsions were prepared by a low energy sub-PIT method. ► The addition of NaBr can reduce the higher PIT of the systems caused by CTAB. ► Mechanism of the method is solubilization of oil into swollen micelles above the TCB. ► Mechanism of the method is solubilization of oil into swollen micelles above the TCB. ► The obtained O/W nano-emulsions have tunable zeta potential and long-term stability.