The aim of our study is to make polymer microcapsules with uniform size and size distribution which can be used in many applications, the most important of these are in medical and pharmaceutical application.
To achieve this purpose, two methods of emulsification were used: conventional method (mechanical stirring) and premix membrane emulsification. These two methods were compared by using different polymers, surfactant and non-solvents.
For preparation of the microcapsules, the polymer solutions (polystyrene or polycaprolactone/dichloromethane) were emulsified in a non-solvent containing a mixture of water and different alcohols with adding different surfactants such as Soduim Loryal Sulfate, Tween (80 and 20) and Np9. The solvent, dichloromethane, diffuses out of the droplets and the polymeric solution surrounding the droplets becomes more and more concentrated and solidifies into a polymeric shell. The light microscope was used to visualize these particles.
It was found that by using water as non-solvent, the smallest average size of particles (2.3µm) was obtained followed by ethyl acetate (3.5µm) and methanol (4µm). SLS was the best surfactant to make stable and uniform polystyrene microcapsules. Whereas Np9 surfactant could be considered as an excellent surfactant to stabilize the polycaprolactone microcapsules and it has high productivity of uniform particles.
Premix membrane emulsification seems to be the method of choice for microcapsules production, because of its simplicity and versatility and it has the best control over size and size distribution than a conventional (stirring) method. Comparing the premix membrane emulsification with the conventional method, the results showed that the size of the microcapsules decreased and size distribution became more uniform when premix membrane emulsification was used to prepare the microcapsules