title: Comb-like ionic complexes of cationic surfactants with bacterial poly(gamma-glutamic acid) of racemic composition.
abstract: Comb-like ionic complexes, nATMA . PG(DL)GA, were prepared from microbial poly(gamma-glutamic acid), with a nearly racemic configuration, and alkyltrimethylammoniun bromides, with linear alkyl chains containing an even number of carbon atoms, n, ranging from 12 to 22. The complexes had a nearly stoichiometric composition, displayed thermal stability up to temperatures above 200 degrees C and were insoluble in water but soluble in organic solvents. In the solid state, they were arranged in a regularly layered structure with the alkyl side chain crystallized for n > or = 18. Heating above melting entailed a contraction in the interlayer distance which varied from 1 to 10% depending on the value of n. Comparison with data reported on similar complexes obtained from nearly enantiomerically pure poly(gamma-glutamic acid) revealed an overall behavior very similar for the two series but with specific significant differences concerning side chain crystallinity and dimensional response to temperature.
authors.affiliation: Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, ETSEIB, Diagonal 647, 08028 Barcelona, Spain.
authors.forename: Monserrat
authors.initials: M
authors.lastname: García-Alvarez
authors.forename: José
authors.initials: J
authors.lastname: Alvarez
authors.forename: Abdelilah
authors.initials: A
authors.lastname: Alla
authors.forename: Antxon
authors.initials: A
authors.lastname: Martínez de Ilarduya
authors.forename: Concepción
authors.initials: C
authors.lastname: Herranz
authors.forename: Sebastián
authors.initials: S
authors.lastname: Muñoz-Guerra
mesh_terms: D002244:Carbon / Q000737:chemistry; D002412:Cations; D006358:Hot Temperature; D007477:Ions; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008968:Molecular Conformation; D010455:Peptides / Q000737:chemistry; D011099:Polyglutamic Acid / Q000737:chemistry*; D011108:Polymers; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013816:Thermodynamics; D014961:X-Ray Diffraction
chemical_list: D002412:Cations; D007477:Ions; D046911:Macromolecular Substances; D010455:Peptides; D011108:Polymers; D000644:Quaternary Ammonium Compounds; D011099:Polyglutamic Acid; D002244:Carbon