794587-41-0Relevant academic research and scientific papers
Liquid crystalline properties of polyguanidines
Kim, Jeonghan,Novak, Bruce M.,Waddon, Alan John
, p. 8286 - 8292 (2004)
Modified polyguanidines were prepared, and their liquid crystalline properties were studied using optical polarizing microscopy and X-ray diffraction. Parameters examined include chirality, the uniformity of the lengths of side chains, and attached side-chain mesogens. If the side chains on the repeat units are identical, then polymer has a more ordered structure in both solution and the solid state. Uniform lengths of the side chains are also important. Poly(N,N′-di-n-hexylguanidine), poly-I, exhibited a lyotropic smectic texture in contrast to a nematic texture of poly(N-(rac)-2-phenylethyl)- N′-methylguanidine) (poly-(rac-II)). Optically pure poly(N-((R)-2- phenylethyl)-2-methylguanidine) (poly-(R-II)) formed a cholesteric texture, whereas the corresponding racemic polyguanidine, poly-(rac-II), formed a nematic texture. Additionally, poly-(R-II) displayed a mesophase at a lower critical concentration than either poly-I or poly-(rac-II), implying that poly-(R-II) is suffer than these two other derivatives. Polyu(N-6-((4′-methoxyphenylazo) phenyl-4-oxy)hexyl-N′-n-hexylguanidine) (poly-IV), one of combined liquid crystalline structures (liquid crystalline backbone plus liquid crystalline side chains), displayed a lyotropic nematic texture presumably due to the strong dipolar-dipolar interaction between the main chain and side chains that folds the appendages parallel to the molecular axis. Poly(N-12-((4′- methoxybiphenyl-4-oxy)dodecyl-N′-n-dodecylguanidine) (poly-V) and poly(N,N′-di-n-dodecylguanidine) (poly-VI) exhibited thermotropic liquid crystalline behavior.
