Encapsulation in colloidal particles
Colloidosome Colloidosomes are microcapsules whose shells consist of coagulated or fused colloid particles. They allow a great degree of control on the shell permeability by varying either the size of colloid particles or degree of fusing.
In our project, 10μm colloidosomes are made with latex particles (200nm) to create water-in-oil microcapsules. The latex particles self-assemble at the water/oil interface to stabilize the emulsion droplets [Yow and Routh(2006)]. This is due to the presence of electrostatic attraction between the negatively charged latex particles and cationic surfactants. The migration is also encouraged by the minimization of interfacial energy. These colloidosomes are further stabilized by sintering, thus locking the colloid particles. They can be re-dispersed into an aqueous phase to create water-in-water microcapsules. The advantage of our technique lies in the simple solvent-free procedure, combined with low processing temperatures, up to 55℃, thus allowing the possibility of bio-related applications.
With successful formation, we are now interested in characterizing the colloidosomes, including the mass transfer and mechanical strength of the shells. The former is investigated via measuring the release rate of an encapsulated dye over a given time period; while, the latter is determined from the buckling of the shell when immersed in different surfactant solutions.
Yow, H.N. and Routh, A.F. (2006) Formation of liquid core polymer shell microcapsules. Soft Matter 2, 940-949.