Date of Award

6-2002

Document Type

Union College Only

Degree Name

Bachelor of Science

Department

Chemistry

Language

English

Abstract

The field of photonics involves the use of light to acquire, store, process, and transmit information. Nonlinear optical (NLO) materials are crucial for success in the advancement of photonic devices. Laponite and hectorite host assemblies have been shown previously by our group to induce I -aggregation of nonlinear optical (NLO) dyes and offer facile routes to film fabrication. Head-to-tail alignment (J-aggregation) of the NLO chromophores is a required condition for photonic applications. In this study, tetrabutylammonium, triethylhexylammonium, trimethyldodecylammonium, and trimetylcetylarunonium surfactants were utilized to render the smectic intergallery region organophilic thus facilitating chromophore intercalation and an increased J-aggregated dye fraction. Fourier transform infrared spectroscopy and powder X-ray diffraction were used to probe the interlayer structure and phase state of the intercalated alkylammonium surfactants by monitoring frequency shifts of the CH2 stretching vibrations and gallery height as a function of packing density and chain length. As the chain length or interlayer packing density increased, the chains adopted a more ordered, lamellar structure leading to two-dimensional ordering of clay tactoids. Organically modified laponite was subsequently loaded with two NLO chromophores, disperse red! (DSRI) and disperse orange 3 (DS03), and the effects of surfactants on the extent of J-aggregation were studied. The nature of dye aggregation was characterized using UVNIS spectroscopy. We report herein that modifying laponite tactoids with surfactants allows for selective control over nonlinear optical chromophore aggregation. In addition, the presence of surfactant within the host framework affords the possibility of higher dye loadings ofDS03 and DSRI as well as inducing a higher fraction of J-aggregates of DSRI than previously reported.

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