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Microcontact printing ($\mu$CP) is a type of soft-lithography technique, which is widely used for patterning self-assembled monolayers (SAMs). It is a convenient method to form SAMs of bio/chemical ink onto different surfaces such as polymers, palladium, silver and gold. A wide range of applications of this technology includes micromachining, patterning proteins, cells or DNA in biosensors. However, the application primarily depends on the type of the ink used. Here, we present an experimental study that provides information about the parameters that affect the $\mu$CP process. Two different thiol inks (dithiothreitol (DTT) and glutathione (GSH)) have been used for obtaining SAMs on gold-coated substrates. Our findings suggest that transferring the alkanethiols over the gold surface is extremely dependent upon the molecular weight of thiol compound, concentration of the thiol solution and pH value of the buffer used. Furthermore, higher the molecular weight, concentration and pH value of the ink, lower is the time required for the process of $\mu$CP.

For most practical applications, it is essential to fabricate micro- or nano-scale polymer electroluminescent (EL) devices and pixel arrays. Microcontact printing, which uses a patterned elastomer (usually PDMS) as the mold to generate or transfer the pattern offers immediate advantages. Here we describe a method of patterning polymeric EL materials based on microcontact printing using PDMS mold. In this technique, we use the self-assembled monolayer (SAM) system of alkanephosphonic acids on ITO substrate, and patterned EL polymer is formed on the SAM-modified ITO substrate.

The fabrication of nanodevices and nanosystems having dimensions smaller than 100 nm requires the ability to produce, control, manipulate, and modify structures at the nanometer scale. Physical and chemical nanolithography techniques have been demonstrated to be promising because of the low cost and high throughput. Although the physical and chemical nanolithography techniques can pattern small features on single chips or across an entire wafer, there are considerable challenges when dealing with complex nanostructures, alignment and multilevel stacks. In this paper, the problems are reviewed and potential solutions suggested.

Highly ordered arrays consisting uniform fluorescent cadmium selenide (CdSe) quantum dots (QDs) ring or dot structures were obtained by self-assembly of QDs on chemically patterned substrates. In this method, Au substrates with alternating hydrophobic and hydrophilic square patterns are firstly fabricated by microcontact printing, which allows water droplets to condense on the hydrophilic regions to provide two-dimensional template arrays. The CdSe QDs are then assembled at the liquid/liquid interfaces to give uniform micro or nanostructures. The shape and size of the rings and dots can be tailored by controlling the relative evaporation speed of the water and the organic solvents. The obtained nanostructures have ideal topography to avoid substrate-induced fluorescence quenching.