Liquid crystalline polymer networks

Preparation of a photovoltaic cell comprising an interconnecting liquid crystalline polymer network of reactive mesogens... 

A third mesogenic monomer, (III), was also used to prepare liquid crystalline polymer networks and is illustrated below. 

TABLE 1. Physical Properties of Interconnecting Liquid Crystalline Polymer Networks of Reactive Mesogens ... 

Liquid crystalline polymer networks were prepared by Kelly et al. (1) with mesogenic monomers, (IV), and used in forming networks charge-transporting or luminescent materials. 

In recent years, the behaviour of liquid crystalline polymers including elastomers has been a subject of considerable interest 104,105). It is known that small molecule liquid crystals turn into a macroscopic ordered state by external electric or magnetic fields. A similar behaviour seems to occur for liquid-crystalline polymer networks under mechanical stress or strain. 

Kurihara, S., Sakamoto, A., and Nonaka, T. Fast photochemical switching of a liquid-crystalline polymer network containing azolwnzcne molecules. Macromolecules 31. 4648... 

Figure 2.31 is an example of a liquid crystalline polymer network which is the crosslinked product of crosslinkable liquid crystalline polymers and the crosslinking agents. 

Figure 2.31. An example of forming a liquid crystalline polymer network. (From Sirigu, 1993.)...

PHOTOELASTIC BEHAVIOR OE LIQUID CRYSTALLINE POLYMER NETWORKS... 

Fig. 1 Synthesis of liquid crystalline polymer networks (x,y,z are the numbers of monomer units of one polymer chain x+y+z = 120 m is the number of methylene units of the flexible spacer)...

Ahn, S.K., Deshmnkh, P. and Kasi, R.M. (2010), Shajie memory behavior of side-chain liquid crystalline polymer networks triggered by dual transition temperatures. Macromolecules. 43(17) pp. 7330-7340. 

When the UV-curing process is performed in the isotropic phase conditions, polygonal or continuous phase-separated stmctures of liquid crystalline polymer networks are obtained for the dissimilar mesogenic blends... 

Dasgupta D, Shishmanova IK, Ruiz-Cairetero A, Lu K, Verhoeven V, van Kuringen HPC, Portale G, Leclere P, Bastiaansen CWM, Broer DJ, Schenning APHJ (2013) Patterned sUvct nanoparticles embedded in a nanoporous smectic liquid crystalline polymer network. J Am Chem Soc 135(30) 10922-10925... 

Besides their liquid crystallinity reactive mesogens exhibit an additional feature. They carry functional groups, such as oxetanes or acrylates, which can be polymerized and densely crosslinked polymer networks are formed. If the crosslinking takes place in the liquid crystalline phase of the material, then the liquid crystalline order is preserved in the resultant polymer network, which is thermally stable up to the decomposition temperature of the polymer network. Furthermore, the liquid crystalline polymer network becomes completely insoluble upon crosslinking, which allows the preparation of multilayer devices using solution processes. In many cases the crosslinking is carried out by a photochemically initiated reaction. 

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