Liquid crystalline gels, elasticity

Cubic liquid crystalline systems have been described as clear, stiff gelsJ As such, they show shear thinning after an apparent yield stress has been exceeded. The viscoelastic properties are also typical for the gel character a broad linear viscoelastic range and a frequency-independent elastic component, which is considerably higher than the viscous component, are observed. ... 

In this chapter, we first describe the stmcture of networks, followed by the discussion of the simple classical models of elasticity and the more advanced theories such as the constraint and the tube models. We also give the molecular interpretation of coefficients obtained from the phenomenological theories. Some simulations relevant to mbberlike elasticity are then described, followed by a discussion of responsive gels because of their increasing interest to many groups. We then discuss the thermoelastic (force-temperature) behavior of networks, followed by the information on multimodal networks, liquid-crystalline (LG) elastomers, novel reinforcing fillers, and characterization methods. 

Finally, it is worth mentioning that PVA cryogels are able to incorporate different soluble and insoluble additives inside the pores to obtain composite materials of both scientific and applied interest [4—6]. In particular, PVA-based cryogels have been obtained that include inside the porous structure nanoparticles of solid crystalline compounds, co-elastic gels, microorganisms, gas bubbles, or microdroplets of liquids immiscible with PVA solutions [4—6, 92-98]. 

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