Printing of Au nanoparticles by VUV-exposed patterned surfaces of a poly(dimethylsiloxane) film

This paper dealt with exposure of a nanometer-level flat cross-linked poly(dimethylsiloxane) film to vacuum ultraviolet light (VUV) at a wavelength of 172 nm and its application to printing of Au nanoparticles. FTIR and contact angle measurements allowed us to confirm the formation of a silica outermost layer on the PDMS film due to photo-oxidation of a methylsilyl group to a silanol group and condensation to a Si-O-Si moiety. It was indicated by AFM observation on a PDMS film surface patterned by imagewise VUV-exposure that the height of VUV-exposed regions was lower than that of unexposed regions by approximately 10 nm due to shrinkage by condensation among the photogenerated silanol groups. Location-selective inking of an Au-nanoparticle/toluene solution was possible on the VUV-exposed patterned PDMS surfaces. Au-nanoparticle micropatterns in about 30 Pm size were successfully transcribed on a silica substrate surface from the inked PDMS film.