Critical Packing Parameter CPP for Emulsifier Selection

The critical packing parameter (CPP) is a geometric expression relating the hydrocarbon chain volume (v) and length (1) and the interfacial area occupied by the head group (a) [30], 

Regardless of the shape of any aggregated structure (spherical or cylindrical micelle or a bilayer), no point within the structure can be farther from the hydrocarbon-water surface than Ic- The critical chain length, is roughly equal to, but less than, the fully extended length of the alkyl chain. 

The CPP for any micelle shape can be calculated from simple packing constraints. 

V is the volume of the hydrocarbon chain and n is the aggregation number. The cross sectional area of the hydrocarbon chain is given by Eq. (6.42). 

---