Diluted Solution Behavior and Chain Rigidity of a Chiral Crust Liquid Crystalline Polymer

A type of side chain type liquid crystal polymer 111 that is directly attached to the main chain in a waisted manner. Due to the dense arrangement of the rigid, bulky liquid crystal elements, the main chain of the molecules is forced to adopt an extended conformation so that the main chain can be surrounded There is enough space for this kind of liquid crystal polymer to have certain morphological characteristics and properties of the backbone-chain liquid crystalline polymer. 12. Recently, we have used radical polymerization to synthesize a class of side groups that are cross-linked to terphenyls. Reactive crust type liquid crystal polymer poly (4,4-bis (sec-butoxycarbonyl) 2-vinyl terphenyl) (PBBCTB), through the comparison of monomer and polymer in optical activity, circular dichroism, etc. It is preliminarily believed that the polymer takes a helical conformation in a certain direction in solution. The helical structure is a rigid structure and the corresponding polymer should have an extended chain conformation. From the static and dynamic laser light scattering, important molecular parameters such as weight average molecular weight MW, root mean square rotation radius z 1/2, second virial coefficient â–², and hydrodynamic radius Ri can be obtained, and they are intrinsically viscous 1. Light scattering (LS) ) Light intensity, 5 intervals. The solvent was chromatographically pure THF and the polymer solution was prepared with a pore size of 0. The pore filter was filtered directly into a light scattering standard tube. Under the above conditions, the refractive index increment (dn/dc) of the polymer sample is the scattered light intensity of the polymer solution in the static light scattering, that is, the increase, the refractive index of the solvent, and the wavelength of the incident light in the vacuum, c The solution concentration, 0 is the scattering angle. According to formula (1), using Zimm mapping, we can obtain Mw, <Rg2>z1/2, A2. Calculation of the hydrodynamic radius Rh. 2 Results and discussion 2.1 The solution behavior of the polymer by static light scattering method, Using toluene as a reference standard, the light scattering intensity and its angular dependence data of 30150 in different concentrations were measured and compared with poly(n-decyl-(S)-2-methylbutylsilane)18. The q-value of the polymer PBBCTB is significantly lower, and thus it can be considered that the polymer PBBCTB is similar to PBMBS and exists in a stretched rigid chain conformation in a tetrahydrofuran dilute solution. From the molecular structure point of view, PBBCTB is different from general side chain type liquid crystal polymers in that it directly attaches the teri-phenyl group as a liquid crystal element to the flexible polystyrene main chain in a lumbar connection. The para-terphenyl and the chiral carbon atoms attached to the ester bond make the side groups bulky and rigid, and their dense arrangement in the space around the backbone forces the polymer backbone to adopt an extended chain conformation in solution. And show the characteristics of a rigid chain.

The above results indicate once again that such a shell-type liquid crystal polymer, which is different from a general side chain type liquid crystal polymer, has a molecular chain rigidity closer to that of a main chain type liquid crystal polymer in a solution. Chemical Journal of Wuhan (Wuhan) Press School) 2000 Yi (Plenty-friendly) Research and Research Key Project (Project No. 01001) Supported Projects; Correspondence of Communications, E-mail: