Preparation of Polymer and Hybrid Colloids by Miniemulsion for Biomedical Applications
I. INTRODUCTION The formulation and application of polymer particles and hybrid particles composed of polymeric and inorganic material is of high interest for biomedical applications. For such applications, it is necessary that the materials or especially the surface of the particles are biocompatible, nontoxic, and sometimes also biodegradable. Many different approaches are used for the generation of nanoparticles in order to obtain the needed properties. For the preparation of polymer particles, processes such as microemulsion  and emulsion polymerization  are used that are based on a kinetic control during the preparation; the particles are built from the center to the surface, and the particle structure is governed by kinetic factors. Due to the dictates of kinetics, serious disadvantages, such as lack of homogeneity and restrictions in the accessible composition, have to be accepted. Therefore, it is desirable to take advantage of a potential thermodynamic control for the design of nanoparticles and the concept of “nanoreactors” whereby the essential ingredients for the formation of the nanoparticles are present at the beginning . It should be emphasized that particle formation in nanoreactors takes place in a highly parallel fashion, i.e., the synthesis is performed in 1018-10 20 nanocompartments per liter that are separated from each other by a continuous phase. However, previous systems show serious restrictions and failure mechanisms, as recently discussed .