Experiments were conducted on subcooled boiling at 30 degrees C on a heated wire of d = 50 mu m in diameter and a heated tube of d = 1.5 mm in diameter considered as micro-scale and macro-scale heaters, respectively. For boiling on the wire of d = 50 mu m submerged in water, jet flow due to surface tension gradient played an important role in promoting heat transfer from the wire to the liquid. For subcooled boiling on the wire of d = 50 mu m submerged in surfactant solutions, jet flow was not observed. The adsorption of surfactants at the vapor-liquid interface of the bubble creates a surface excess concentration gradient, which acts in the opposite direction to the imposed temperature gradient and it results in the reduction of thermo-capillary convection around the bubble. The experimental data obtained under conditions of boiling on the wire of d = 50 mu m in surfactant solutions showed different behavior of boiling curves compared to those obtained for macro-scale boiling. The boiling curves obtained during boiling on micro-scale heater are not dependent on surfactant concentration. When surfactants are present in water, there is generally a reduction of the overall or combined thermo-capillary and diffuse-capillary Marangoni convection. (C) 2015 Elsevier Ltd. All rights reserved.