Measurement of the interfacial tension of a phase-separated colloid-polymer suspension

We studied the interfacial tension between coexisting colloid-rich and poly mer-rich fluid phases in a phase-separated colloid-polymer mixture. First, the location of the fluid-fluid binodal and the tie lines between the coexi sting phases were determined using a recently proposed method that only req uires the volumes of the coexisting phases as input. The spinning drop meth od was used to determine the very low interfacial tension between the coexi sting phases. We also used the dynamics of the breakup process of the dropl et of one phase suspended in the other to determine the interfacial tension .