Plasticizer-assisted polymer imprint and transfer

Abstract

We have developed a new method to pattern polymeric materials, including non-thermoplastic polymers, at low temperature and low pressure. In this method, plasticizers are added to increase the chain mobility of the polymers, resulting in lower imprinting temperature and/or pressure. Two established imprinting and transfer techniques were chosen to demonstrate this method, namely, conventional nanoimprint lithography (NIL) and microcontact printing (μCP). These two techniques were used to pattern poly(3,4-ethylenedioxythiophene) (PEDOT). PEDOT was chosen because it is a non-thermoplastic polymer and therefore cannot be easily patterned using conventional NIL. Successful imprint of PEDOT films from the PDMS mold was achieved at a low pressure of 10 kPa and 25°C by controlled addition of glycerol as a plasticizer using conventional NIL; well-defined arrays of 2μm wide, 185 nm high PEDOT dots have also been demonstrated by μCP. In contrast, patterning of PEDOT film without plasticizer requires higher temperature (80°C) and pressure (10 MPa), which could cause severe deformation of the transferred patterns. This method of plasticizer-assisted imprint lithography (PAIL) broadens the applicapability of NIL to a wide range of polymeric materials.