Poly-y-heptyl-L-glutamate

As stated already, the sign of cholesteric twist of the solution of PBLG in CHCl is opposite to that in dichloroethane. The cholesteric twist of PALG also behaves in the same manner, that is, the sign is different to each other in the two solvents. However, the nematic temperature of PALG in EDC increases with the increase of alkyl chain length in the side chain. The constant n, then can be obtained from the plot of log 1/S against log C in EDC. It 

The difference between PBLG and PALG may be in their side-chain conformation. As already pointed out, the side chain of PBLG is not fully extended. 

Magnetic Reorientation and Counterrotation in Poly(y-Benzyl Glutamate) Liquid Crystals 

Poly(Y benzyl glutamate) (PBG) is a synthetic polypeptide which adopts the a-helical conformation in various organic solvents. Its essentially rod-like shape is responsible for the formation of a liquid crystalline phase above a critical concentration of polymer (l 2). The nature of this mesophase is usually cholesteric due to the chirality of the PBG molecules but 

NMR spectra were recorded on a Varian HA-100 spectrometer in an unlocked mode using an external oscillator and frequency counter to calibrate its sweep parameters. Samples were equilibrated in the magnetic field without spinning at ambient temperature (ca. 32 0) for nearly a day before each reorientation. The temperature was controlled with a precision of 0.2 with a Varian temperature-control unit. The samples were rotated by accurately known amounts with the aid of small aluminum sleeves 

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