Ostwald Ripening Rate of Two-Component Miniemulsion Systems

The effect of varying the costabilizer volume fraction on the Ostwald ripening rate of various two-component miniemulsion systems comprising of either methyl methacrylate (MMA) or styrene (STY) as monomers, stabilized by either lauryl methacrylate (LMA) or stearyl methacrylate (SMA) was investigated. The Ostwald ripening rate was found to decrease with increasing costabilizer content in the monomer mixture. Systems stabilized by the more hydrophilic LMA show higher Ostwald ripening rates as compared to systems stabilized by SMA. It was found that the Ostwald ripening rate follow Kabalnov s equation 1/ = 1/ 1 + 2/ 2 only at low costabilizer volume fractions, deviating significantly as the costabilizer volume fraction is increased. An empirical equation 1/ = 1/ 1 (1+K1 2+K2 22) was fitted into the experimental values of the Ostwald ripening rate. This gave satisfactory values of the coefficient of determination (R2). The effect of varying the finite disperse phase volume fraction on the Ostwald ripening rate was also studied. It was shown that changing the volume fraction of the disperse phase does alter the Ostwald ripening rate.