Effect of surfactants mixing of Tween 80 and Nonidet RK-18 in preparation of microspheres based on polyblend of poly(lactic acid) and polycaprolactone

In preparation of microspheres process with solvent evaporation method, microspheres are formed from the oil in water (O/W) emulsion droplets as a template in which the type and concentration of surfactant will affect the stability of the emulsion. This research aims to investigate the effect of composition and concentration of a mixture of Tween 80 and Nonidet RK-18 as a mixed emulsifier in the preparation of microspheres based on polyblend of PLA/PCL. The solvent evaporation method involves emulsification and dispersing the polyblend emulsion in water. The microspheres obtained were characterized using FTIR, stereomicroscopes, and PSA instrumentations. The result of this research shows that the mixed emulsifier produces smaller microspheres compared to the result of using Tween 80 or Nonidet RK-18 individually because of the presence of synergistic effect. When the surfactants mixture is used, the larger Tween 80 ratio in the mixture will increase the ratio of smaller microspheres obtained because of the high hydrophilicity of Tween 80 that can stabilize O/W emulsion. On the other hand, the addition of Nonidet RK-18 in an increasing manner of ratio or concentration may destabilize the emulsion droplets through Ostwald ripening that can occur because Nonidet RK-18 has a low cloud point (17 °C).