7.5 Size Distribution of Droplets

A factor influencing the rate of coalescence of the droplets is the size distribution. The smaller the range of sizes，the more stable the emulsion. Since large particles have less interfacial surface per unit volume than smaller droplets，in macroemulsions they are thermodynamically more stable than the smaller droplets and tend to grow at the expense of the smaller ones.^④ If this process continues，the emulsion eventually "breaks". An emulsion with a fairly uniform size distribution is therefore more stable than one with the same average particle size having a wider distribution of sizes.