modulus at a quite smallGvalue (expressed in mg?m^2 ), whereas for
b-caseinESDwould be very small forG<1mg?m^2. Hence prevention of
recoalescence would be less. Most small-molecule surfactants are indeed
superior in preventing recoalescence as compared to proteins. It may further
be noted that Figure 11.13 will even overestimate the value ofESDfor
b-casein, because thePvalue will be smaller for the sameGvalue at the very
short time scales involved; this is discussed in Section 10.8.2.
An important characteristic of an emulsion is whether oil or water
makes up the continuous phase. This is governed byBancroft’s rule, which
FIGURE11.13 Surface pressureP versus ln(surface excess,G) at the O–W
interface for sodium dodecyl sulfate andb-casein.