Monolayers of long-chain fatty acid esters evolve irregularly shaped morphological structures depending on the existing conditions of spreading. A reproducible evolution of defined circular condensed phase domains is achieved by a heating-recooling cycle at a fixed area per molecule in the surface pressure region of about 0 mN m(-1). The mechanism of domain growth is qualitatively related to a nucleation-growth mechanism. Besides the condensed phase domains that coexist with the fluid phase of low density, random cellular structures appear in it which evolve to a two-dimensional network of boundary lines under the influence of the temperature gradient. The cellular patterns within this phase of low density are accounted for by dissipative structures induced by temperature gradients.