Spontaneous buckling of compressible droplet chains in free standing smectic-C films.

Isotropic spheres or droplets dispersed in a smectic freely suspended film can self-organize in chains that interact with the c-director field of the embedding smectic material. Spontaneous buckling of such chains has been reported when the chains grow under geometrical restrictions, by incorporation of additional droplets. We refine the original model for incompressible chains by taking into account a finite energy associated with the variation of the intrachain droplet-droplet-distance. In addition to the wavelength selection described already by the inelastic chain model, the refined model yields a critical threshold for spontaneous buckling, in agreement with experimental observations.