Spontaneous capillary breakup of suspended gradient polymer stripes into spatially ordered dot arrays

We describe the experimental study on the spontaneous capillary instability of gradient poly(methyl methacrylate) (PMMA) stripes beneath the continuous polystyrene (PS) film. Upon vapor annealing using a selective solvent only for PMMA, the PMMA stripes were transformed into well-ordered dot-arrays beneath the continuous PS film via capillary force driven rupture. Dimensional features of the PMMA dots strongly did not depend upon the initial width and height of the PMMA microscopic stripes. Repeatedly, such this gradient stripe geometry triggered a competition between the phase correlation of neighboring stripes and the kinetically favorable wavelength, thus leading to the formation of an intriguing, recursive surface sub-patterns.