title: Dichroic ATR-FTIR spectroscopy on oriented α-helical poly(l-lysine) multilayered with polyanions.
abstract: The preparation and spectroscopic and microscopic characterization of oriented polyelectrolyte multilayers (PEM) interesting for defined nanostructured functional materials and surfaces are reviewed. Oriented PEM were generated by consecutively adsorbing α-helical poly(l-lysine) (PLL) and oppositely charged polyanions like poly(vinylsulfate) (PVS) or poly(styrene sulfonate) (PSS) at silicon substrates texturized by parallel nanoscopic surface grooves, respectively. Dichroic Attenuated Total Reflexion Fourier Transform Infrared (ATR-FTIR) spectroscopy was used to study the conformation and macromolecular order of stiff polyelectrolytes within PEM. High order parameters up to S=0.82 (S=1 for high, S=0 for low order) were obtained from the dichroic ratios of the Amide I and Amide II bands suggesting a significant alignment of charged α-helical polypeptides in PEM. For PEM consisting of PLL/polyanion the S values significantly increased with increasing molecular weight of PLL and with decreasing molecular weight of the polyanion. These spectroscopic findings were supported by SFM images on PEM-PLL/PVS with high molecular PLL and PEM-PLL/PSS with low molecular PSS, which both showed anisotropically oriented worm-like structures, while PEM-PLL/PVS with low molecular PLL and PEM-PLL/PSS with high molecular PSS showed no orientation features.
authors.affiliation: Leibniz Institute of Polymer Research Dresden e.V. (IPF), Hohe Strasse 6, D-01069 Dresden, Germany. mamuller@ipfdd.de
authors.forename: M
authors.initials: M
authors.lastname: Müller
authors.forename: W
authors.initials: W
authors.lastname: Ouyang
authors.forename: B
authors.initials: B
authors.lastname: Kessler
mesh_terms: D008968:Molecular Conformation; D018583:Pliability; D000071228:Polyelectrolytes; D011107:Polylysine / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry; D011145:Polyvinyls / Q000737:chemistry; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*
chemical_list: D000071228:Polyelectrolytes; D011107:Polylysine; D011108:Polymers; D011137:Polystyrenes; D011145:Polyvinyls; C019050:polyvinyl sulfate; C003321:polystyrene sulfonic acid