Block Copolymer Thermoplastic Elastomers for Microcontact Printing

Two commercial thermoplastic block copolymer elastomers with a high stiffness were investigated as stamp materials for microcontact printing and compared to conventional poly(dimethylsiloxane) (PDMS). Stamps with a relief structure were produced by hot embossing techniques, utilizing the thermoplastic properties of these rubberlike block copolymers. It is shown that the stamps based on these copolymers are able to transfer a thiol ink to a gold substrate. After printing, the thiol ink acts as an etch resist, which indicates that a coherent self-assembled monolayer is formed. Like PDMS stamps, specific copolymer stamps can be used for repeated printing without re-inking. Moreover, the higher stiffness of the thermoplastic stamps increases the load above which structural collapse occurs by a factor of 10−15 in comparison to that of identical PDMS stamps, which is potentially useful in the reproduction of structures which are sensitive to sagging, buckling, or pairing. An example is presented of relief structures, which are accurately reproduced with the thermoplastic elastomers, in contrast to identical chemically cross-linked PDMS stamps.