Transfer printing water-soluble inorganic salts

This paper reports the first example of the fabrication of KNO3, K2CO3, CuSO4, NaOH, and mixed-inorganic-salt (KNO3 and KOH) patterns using a transfer-printing (TP) technique. The transfer quality is found to be related to the concentration of the salt solutions. By varying the immersion time, it is possible to control the heights of the raised features of the transfer-printed salts from the nanoscale to the submicrometer scale. Utilizing these inorganic salts as water-soluble masks for microfabrication is demonstrated using patterned NaOH films. The use of water as a developer solvent demonstrates the potential utility of the patterning of inorganic salts as a low-cost, simple, and, more importantly, environmentally friendly route towards accurate patterning of different materials. KGaA.