Nanoscale investigations of the condensed states of colloidal particles in confined regions provide useful results for both theoretical and experimental materials research. In particular, colloidal particles encapsulated in giant vesicles (GVs) have attracted much attention for the investigation of entropy effects in statistical physics and soft matter science. GVs with encapsulated colloidal particles undergo shape changes due to entropic interaction. In this paper, polyhedral configurations of GVs were observed for the first time using confocal laser scanning fluorescence microscopy. This characteristic configuration was associated with the coexistence of crystallized and disordered phases of colloidal particles in the GVs. Several triangular faces of crystals for colloidal particles formed on the GV membrane were identified. The characteristic patterns of colloidal particles observed in such faces corresponded to close-packing structures and suggest an orderly array of particles. However, the disordered phase was retained at the central part of the GV. For material research, it should be stressed that colloidal particles encapsulated GVs are useful for the investigation of condensed states appearing in the neighborhood of boundary composed of soft matters.
2016 The Materials Research Society of Japan