Relative stabilities and self-alignment tendencies of peptide-based NLO materials

摘要

s are being made to produce nonlinear optical (NLO) polymers by capitalizing on self-alignment properties of peptides by the formation of a beta pleated sheet. Such polymers contain both hydrophilic chromophores and hydrophobic side chains in which selective wetting on a water surface using Langmuir-Blodgett techniques creates a first-order approximation of the oriented film. Assembly to the planar beta pleated sheet structure should further enhance the oriented chromophoric structure of the extended mass. However, this requires stabilization through both hydrogen bonding and through energetically stable conformations. It is this stabilization which will favor the enhanced chromophore alignment during the deposition processes. Previous experimental peptides using leucine-based hydrophobic groups and dinitrophenyl-based hydrophilic chromophores have shown limited success in formation of the oriented films. Because it is desirable to be able to predict the effects of the side chain on orientational properties we have added molecular modeling to our general synthetic strategies, in order to analyze the possible affects of the primary structure on the beta sheet.