AVS 56th International Symposium & Exhibition
    Biomaterial Interfaces Thursday Sessions
       Session BI-ThP

Paper BI-ThP9
Interferometric Lithography of Self-Assembled Monolayers

Thursday, November 12, 2009, 6:00 pm, Room Hall 3

Session: Biomaterial Interfaces Poster Session II (Arrays, Sensing, Micro/Nanofabrication, SPM)
Presenter: J. Adams, University of Sheffield, UK
Authors: J. Adams, University of Sheffield, UK
G. Tizazu, University of Sheffield, UK
S.R.J. Brueck, University of New Mexico
G.J. Leggett, University of Sheffield, UK
G.P. Lopez, University of New Mexico
Correspondent: Click to Email
Self-assembled monolayers (SAMs) have proved to be highly versatile systems for molecular patterning. Previous work using near-field optical methods has demonstrated that exceptional spatial resolution may be achieved using SAM resists, by exploiting the fact that the photosensitive group is confined to a monomolecular film adsorbed to a solid surface. However, near-field methods are serial in nature. Here we have exploited interferometric approaches in combination with SAM resists to fabricate a variety of nanostructured materials. Extremely high resolution has been achieved by exploiting the monolayer nature of the resist. Interferometric lithography (IL) is rapid, and uses minimal instrumentation. IL using a cw, 244 nm frequency doubled Ar-ion laser source has been found to yield structures as small as 35 nm using SAM resists, over macroscopically extended areas. SAMs of alkanethiols on gold may be photo-oxidized to yield weakly bound sulfonates that may be displaced by solution-phase adsorbates to yield patterns of chemical composition. Here, we demonstrate the fabrication of patterns of surface free energy with a period of 200 nm. Protein adsorption may be controlled by using IL to selectively photodegrade oligo(ethylene oxide) (OEG) terminated SAMs of alkanethiols on gold and of trichlorosiloxanes on glass. Nanopatterned streptavidin formed this way retains its ability to bind biotinylated proteins. Finally, monolayers of phosphonic acids on titanium dioxide may be readily patterned and used as templates for the fabrication of a variety of architectures, including 35 nm TiO2 structures on glass. IL is an inexpensive, fast and convenient means of producing molecular nanostructures over square centimetre and larger areas.