The structure of deformable particles in applied external fields

The structure of two dimensional deformable particles of low interfacial tension is studied theoretically. Closed loops in the plane are used to model droplets of one liquid in a second with surface active molecules residing at the liquid-liquid interface. The mechanical properties of the surfactant layer are represented by a bending energy contribution due to Helfrich, where the relevant parameters are rigidity and local curvature, and a surface tension. Thermal shape fluctuations and the deformational response to external fields, such as those due to confining walls or neighbouring particles, are studied by a method of functional integration in conjunction with a Monte Carlo sampling technique. Our results include particle shape distribution functions for different geometrical constraints and interfacial conditions which are relevant to bilayer lipid vesicles, microemulsion particles and emulsion droplets. J. Physique 48 (1987) 465-472 MARS 1987,