Accession Number:

ADA281193

Title:

Polymer Effect on Heterochiral Molecular Recognition in Molecular and Macromolecular Pairs of Liquid Crystals of (R)- and (S)-2-Chloro-4-Methylpentyl 4'-((8-(Vinyloxy)Octyl)Oxy)Biphenyl-4-Caroxylate Enantiomers

Descriptive Note:

Corporate Author:

CASE WESTERN RESERVE UNIV CLEVELAND OH DEPT OF MACROMOLECULAR SCIENCE

Personal Author(s):

Report Date:

1994-06-30

Pagination or Media Count:

54.0

Abstract:

R-2-Chloro-4-methylpentyl 4-8-vinyloxyoctyloxybiphenyl-4- carboxylate R-8 R 95 and S-2 Chloro-4-methylpentyl 4-8- vinyloxyoctyloxybiphenyl-4-carboxylate S-8 S95 enantiomers and their corresponding homopolymers and copolymers with well defined molecular weight and narrow molecular weight distribution were synthesized and characterized. The phase behaviors of R-8 and poly R-8 are identical to those of S-8 and polyS-8 respectively. Both monomers display monotropic SA and SCk phases and a crystalline phase, while the corresponding polymers exhibit enantiotropic SA, SC and SX unidentified smectic mesophases. The SA-I transition of the binary mixture of R-8 with S-8 is with 0.4 deg C higher in the 5050 mixture than the theoretical value expected for an ideal solution, demonstrating the presence of heterochiral molecular recognition between the two enantiomers in their SA phase. Heterochiral recognition was not detected in the SC phase of any of the enantiomeric pairs investigated. In the polymer mixtures, the chiral recognition observed in the SA phase of the monomer mixtures is enhanced with increasing the degree of polymerization DP up to about 10 to reach a positive deviation of 1. 3l deg C from the theoretical ideal value.

Subject Categories:

  • Organic Chemistry
  • Physical Chemistry
  • Polymer Chemistry
  • Crystallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE