Fibers and wires in organogels from low-mass compounds: Typical structural and rheological properties

An overview is given of the special class of thermoreversible organogels and jellies formed with low-mass compounds. Two distinct rheological behaviors can characterize these binary systems: (1) viscoelastic liquids which develop an elasticity over short times, (2) viscoelastic solids which are constituted on long-lived 3-d networks at a temperature T in the gel domain of the phase diagram. Entangled, breakable giant micelles (molecular wires) are opposed to fibers interconnected through crystalline-like microdomains. Certain thermal and rheological properties are presented as well as the detailed structural context at different scales of the fibrillar networks. A brief review of the different chemical classes of organogelators illustrates the growing development in the field. The class of viscoelastic liquids (jellies) is illustrated with the special category of monomolecular organometallic wires.