(288d) Surface-to-Surface Transfer Printing of Liquid Inks

In the literature, several micro/nano-lithographic techniques have been described that are analogous to macroscopic writing and printing methods. For example, micro-contact has been applied to the printing of protein patterns, microelectrode arrays, organic light emitting diodes and organic thin film transistors with sub-micron resolution. Dip pen nano-lithography (DPN) is a scanning probe method that is used to ?write? patterns of monolayers of different organic molecules, with a very high resolution (~5 nm). Currently, the most common technique for the generation of high-density micro-arrays of recognition molecules such as cDNA and antibodies for quantitative analysis of gene expression, protein recognition and identification of potential drug targets, is the use of micro-machined quill pens. All the aforementioned techniques involve the transfer of liquid between surfaces. In this presentation, we will identify the critical parameters that affect the percentage of liquid transferred from one surface to another and develop a mathematical model that will predict the extent of liquid transfer for different parameter values. We will also demonstrate the controlled transfer of arrays of pico-liter droplets of different inks from a large initial volume (~10 ìl), using these parameters. So by appropriate choice of relevant physical and operational parameters, micrometer-sized patterns can be obtained using a print head merely comprised of a large droplet of ink on a flat surface.