Poly(N-isopropylacrylamide) microgels at the oil–water interface: temperature effect

The heptane–water interfacial tension exhibits a minimum in the presence of PNIPAM microgels, particularly in the vicinity of the volume phase transition temperature (VPTT) of PNIPAM microgels. The origin of such interfacial tension minima contributes to the microgel spreading at the oil–water interface in the early states and is then governed by the microgels' packing and interactions in the final static equilibrium states.