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Low-molecular-mass organogelators (LMOGs) based on photochromic molecules aggregate in selected solvents to form gels through various spatio-temporal interactions. The factors that control the mode of aggregation of the chromophoric core in the LMOGs during gelation, gelation-induced changes in fluorescence, the formation of stacked superstructures of extended π-conjugated systems, and so forth are discussed with selected examples. Possible ways of generating various light-harvesting assemblies are proposed, and some unresolved questions, future challenges, and their possible solutions on this topic are presented. [ABSTRACT FROM AUTHOR]

We discuss thermally driven transport in both organic solvents and electrolyte solutions and, in particular, the variation of the thermophoretic mobility DTwith temperature. We find that the T-dependence in organic solvents arises from the viscosity η(T), in qualitative agreement with data on polystyrene in ethylbenzene. A more subtle effect occurs for charged colloids in an electrolyte, where the strong correlation of DTwith the thermal expansivity β of water is traced back to the thermoelectric effect. Our results provide an explanation for experiments on various colloidal suspensions and, in particular, for the observed change of sign of DTas a function of temperature. [ABSTRACT FROM AUTHOR]