Hydrophilic Poly(dimethylsiloxane) Stamps for Microcontact Printing

Poly(dimethylsiloxane) stamps for microcontact printing with polar inks,which no longer need to be reactivated after each printing step, are revealed. The silicone surface is modified by linking a hydrophilic polyethylene glycol chain to SiOH groups created on the surface of the stamp. While stamps that are oxidized conventionally become useless 3 h after their preparation (Figure top), the PEG-modified stamps can still print high-quality patterns after 20 days (Figure bottom).