A one-dimensional model for microemulsions is considered. In the model the microemulsion droplets are hard rods that interact through nearest-neighbor pair potentials. Besides the hard core repulsion the interaction presents a square well and a square barrier that have arbitrary width and strength. The thermodynamic and structure properties for this system are found via the isothermal-isobaric ensemble. The model predicts that, under certain conditions, the aggregation number increases with temperature, as is experimentally observed. When the temperature is lowered, the system structure is solid-like and it can be found in two phases with different characteristic wavenumbers.