Thermotropic side-chain LCPs materials

The fairly good quality of the fits validates both Leadbetter s assumptions and the Maier-Saupe distribution function. However, the values of S obtained and even the quality of the fits obviously depend on the odd or even number of (CH2) groups in the flexible spacer. This odd-even effect is widespread and well known in the field of main-chain LCPs and will be discussed later in this article. The nematic order parameter of main-chain LCPs may reach values as high as 0.85 which demonstrates the very high orientation of the nematic phase of these polymers. Such a large orientation is undoubtedly responsible for the good mechanical properties of this type of materials. The treatment described above therefore provides a very easy way of characterizing the orientational order of a nematic phase. It has also been tested for thermotropic side-chain LCPs and found to be satisfactory as well [15]. Unfortunately, it has not been used yet in the case of lyotropic LCPs except for some aqueous suspensions of mineral ribbons (Sect. 5) which are not quite typical of this family of materials. 

Most LCPs of commercial interest are thermotropic main-chain nematic materials. The other main structural type of interest are the side chain LCPs which are generally more complex to synthesise and have not yet found significant commercial applications. The author s Mesogenic Index model, which is useful for predicting whether a given polymer has a mesophase, has been applied only to main-chain LCPs to date. 

In the subsequent chapters dynamic magnetic resonance experiments of thermotropic side and main chain polymers are presented. Computer simulations provide the orientational distributions and conformations of the polymer chains and the correlation times of the various motions. The results, referring to all polymer phases, are related to the exceptional material properties of LCPs. The discussion clearly demonstrates the power of dynamic magnetic resonance in characterizing such complex chemical systems. 

The preparation methods and the novel permselective characteristics of (polymer/LC) composite films have been extensively studied (1-3). Also, various types of (polymer/LC) composite systems have been reported as large area and flexible light-intensity controllable films (4-11). Since thermotropic liquid crystalline polymers (LCPs) with mesogenic side chain groups exhibit both inherent mesomorphic properties of LC and excellent mechanical characteristics of polymeric materials, LCPs... 

---