SMALL MOLECULAR LUMINESCENT GELLING AGENT 2,3-BIS-N-DECYLOXYANTHRACENE - RHEOLOGICAL AND STRUCTURAL STUDY

Luminescent organogels in decane and alcohol solvents of a small molecule, 2,3-bis-n-decyloxyanthracene (DDOA), have been studied by theology and small-angle neutron scattering techniques. When the temperature of a binary DDOA/hydrocarbon or alcoholic solution is lowered, a sharp sol-to-gel transition is observed during the kinetics of DDOA aggregation. A thermoreversible solid-like viscoelastic material with a large yield stress (sigma* approximate to 550 Pa at C = 1% wt) is obtained. The elasticity of the 3D network (G' approximate to 10(4) Pa at C = 1% wt) suggests the existence of numerous and/or strong junction zones as found in some crystalline gels, The scattering experiments have demonstrated the existence of an interface of large bundles of particles with the solvents. If a fiber morphology is considered, the diameters range from ca. 100 to at least 500 Angstrom, in agreement with previous electron microscopy experiments. The DDOA gel crystallinity is correlated with the hexagonal ordering of the related crystalline powder. (C) 1995 Academic Press, Inc.