Molecular conformation of poly(S‐lactic acid)

作者：Pierluigi De Santis, A. J. Kovacs · 发表于：Biopolymers · 年份：1968 · DOI：10.1002/bip.1968.360060305 · 被引用次数：571 · 研究领域：Chemical Synthesis and Analysis、Biopolymer Synthesis and Applications、biodegradable polymer synthesis and properties

Abstract The predominant role of van der Waal interactions in determining the helical conformations of a simple synthetic linear polymer, as well as helical polypeptides, was pointed out in systematic studies by Liquori et al. 1,2 . In the case of homopolypeptides the conformational analysis carried out on the basis of a simple semiempirical function describing the van der Waal pairwise interactions between the non directly bonded atoms lead to the conclusion that only five helices are allowed ( Rα , β, γ, δ, Lα ). 2,3 In view of the close similarities with poly‐ L ‐alanine, we have investigated by x‐ray and conformational analysis the molecular conformation of poly(S‐lactic acid) which has recently been described by Kleine and Kleine 4 and Schuls and Schwaab 5 and studied in solution by Goodman and D'Alagni. 6 In fact, this polymer may be related to the polypeptide by the interchange of a peptide bond with ester bond along the main chain. This operation is expected to involve only a relatively small change in the steric interaction within the possible helical conformation, but obviously rules out any possibility of hydrogen bonding.