Highly fluorescent colloids based on rhodamine 6G, modified layered silicate, and organic solvent

Synthetic layered silicate saponite was modified with dodecyltrimethylammonium (C12), octadecyltrimethylammonium (C18), and dioctadecyldimethylammonium (2C18) cations for use as sorbents of the laser dye, rhodamine 6G (R6G). Via solvent exchange, transparent colloids in xylene were prepared and investigated using absorption and fluorescence spectroscopies. Molecular aggregation and partial quenching of the fluorescence were observed for the colloids based on 2C18 cations. Maximal fluorescence yields were observed for the colloids with C12 and C18 cations. Transparent gels without an apparent loss of luminescent efficiency could be prepared by concentrating the colloids. These highly fluorescent colloids and gels represent new types of materials with interesting optical properties.

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► Colloids based on saponite, alkylammonium surfactants, and rhodamine 6G were prepared.
► The colloids in xylene exhibited unique optical properties.
► In some cases, molecular aggregation was fully suppressed and maximal fluorescence yields were achieved.
► Concentrating the colloids to gels did not apparently affect optical properties of the materials.