Polymer-assisted microcontact printing: Using a tailor-made polydimethylsiloxane (PDMS) stamp for precise patterning of rough surfaces

Rough, capillary-active surfaces remain demanding substrates for microcontact printing (µCP), as the diffusive mobility of the ink thereon drastically limits the printing resolution. To reduce ink smearing, we developed a polymer-supported μCP, which includes a stamp with a polymer brush-decorated surface. The ink molecules are thereby bound into the stamp-bound brush matrix, from where they may be transferred to the substrate, which exclusively occurs during the contact of both interfaces. Conventionally, Slygard184-based polydimethylsiloxane (PDMS) stamps are used for µCP. The material’s surface must be functionalized in a multi-step procedure for the protocol. In addition, Sylgard comes along with a drawback of a persistent leakage oligomeric PDMS (oPDMS), which can contaminate the substrate. To circumvent these problems, we developed a novel stamp material, that (i) enables a straightforward polymer grafting, and (ii) shows a low tendency of oPDMS leakage. We prepare the stamp with a commercially available amino-functional PDMS prepolymer, and a polymer-ic crosslinker that can be used for a controlled photoiniferter reversible addition and fragmentation chain transfer (PI-RAFT) polymerization. The prepared stamp shows elastic properties at the relevant strain region, is compatible with brush formation, and has been demonstrated demonstrated suitable to transfer precise patterns on rough capillary-active oxide surfaces.