Induced mesophase

Note 1 The formation of an induced mesophase usually results from an attractive interaction between unlike species, the strength of which exceeds the mean of the strengths of the interactions between like species. 

Note 4 A monotropic mesophase can be stabilised in a mixture when, as a result of melting-point depression, a metastable mesophase becomes stabilised. Such a mesophase is distinct from an induced mesophase. 

Initial attempts to replicate the idea of using dendronized liquid crystal ligands to induce mesophase formation in magnetic nanoparticles failed for core-shell... 

In the fledgling field of super- and supra-molecular liquid crystals, many different terms have been introduced which describe some of the same structures. Figure 1 shows some classical molecular architectures that can be used to describe the gross structures of super- and supra-molecular liquid crystals. For example, two mesogenic units, i.e., molecular entities that can be deployed in material design in order to induce mesophase formation, can... 

The dipalladium organyls 51, derived from 49 (M = Pd, X = C1) by ligand exchange reaction between the bridging group and acetylacetonate, are not mesomorphic in their pure state, but form mesomorphic charge transfer systems with the electron acceptor TNF [95]. The identity of the induced mesophase is still unknown, but seems very likely to be columnar [96]. Furthermore, lyotropic nematic phases were obtained in the ternary mixture 51/TNF/linear alkane (the binary mixture 51/alkane did not yield mesomorp-hism). The nematic phase in this system is though to have a columnar nature, namely a nematic columnar phase. 

Fig. 2.1.12. Pressure-induced mesophases in p-ethoxybenzoic acid (a) nematic schlieren textures (b) focal conics and batonnets in the smectic phase.

PROPERTIES OF SPECIAL INTEREST Low glass transition temjjerature, mesophase behavior including reversible stress-induced mesophase formation accompanied by necking-denecking phenomena in cyclic deformation of elastomers at room temperature and above. 

Several tetraphenylporphyrins substituted in the four meso positions by various groups have also been investigated, and the induction and stability of mesomorphic properties were found to be dependent on the nature of the side chains. Simple alkyl chains directly connected in the four meso positions of metalloporphyrins ((23) M = Zn, Co, Cu, Ni, Pd) were not sufficient to induce mesophase. 

In spite of the clear analogy between stress-induced mesophase formation and stress-induced crystallization under flow, there is a significant difference between the two processes. Thermodynamically, for a phase transition accompanied by a change in length AL, the relationship between the force/ and the temperature T is given by [71,72]... 

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