Subdiffusive Dynamics of Photo-Addressable Self-Assembled Monolayers

ORAL

Abstract

Self-Assembled Monolayers (SAMs) synthesized on glass and incorporating azobenzene are illuminated with green light at normal incidence to study the effect of photo-isomerization on in-plane molecular orientation. Measurements of the monolayer birefringence at the glass-gas interface show that the SAM orientation and order parameter dynamics are subdiffusive, characterized by a stretched exponential relaxation with a distribution of relaxation times. Order decays with power law relaxation and exponents that decrease with increased initial writing intensity and/or duration, indicative of orientational trapping wells with a distribution of depths. Results on dynamics of reorientation at the glass-solvent interface will also be presented. This work was supported by NSF Grant CHE-0079122 and NSF MRSEC Grant DMR-0213918.

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Authors

  • Guanjiu Fang

  • Noel Clark

  • Joseph Maclennan

    • Department of Physics, University of Colorado, Boulder, CO 80309, USA

  • Matthew Farrow

    • Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA

  • David Walba

    • University of Colorado

  • Youngwoo Yi

  • Thomas Furtak

    • Department of Physics, Colorado School of Mines, Golden, CO 80401, USA