title: Orientation of molecular groups of fibers in nonoriented samples determined by polarized ATR-FTIR spectroscopy.
abstract: A method based on polarized attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy is proposed for determining the infrared dichroic absorption ratio of a single fiber from a sample deposited flat on a germanium crystal without the requirement of fiber orientation. The method shows its efficiency on cellulose fibers of paper and has been applied to protein fibers (type I collagen and β-amyloid) and polysaccharide fibers (cellulose and starch). The method gives access to the dichroic ratio of strong absorptions bands, which is not easily accessible with conventional absorption techniques. Then, the orientation of the molecular groups of organic fibers can be easily determined by polarized ATR-FTIR spectroscopy. By extension, this method will be useful to determine the molecular orientation of fibers in structured complex samples, such as biological tissues and plants. Spatially resolved information on the organization of the fiber network will be easily extracted by utilizing a focal plane array detector for imaging measurements.
authors.affiliation: Laboratoire de Chimie et Biologie des Membranes et Nano-objets, Université de Bordeaux, CNRS UMR 5084, Bordeaux, France.
authors.forename: Karima
authors.initials: K
authors.lastname: Belbachir
authors.forename: Sophie
authors.initials: S
authors.lastname: Lecomte
authors.forename: Ha-Phuong
authors.initials: HP
authors.lastname: Ta
authors.forename: Cyril
authors.initials: C
authors.lastname: Petibois
authors.forename: Bernard
authors.initials: B
authors.lastname: Desbat
mesh_terms: D016229:Amyloid beta-Peptides / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry*; D003094:Collagen / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D013213:Starch / Q000737:chemistry*
chemical_list: D016229:Amyloid beta-Peptides; D011506:Proteins; D002482:Cellulose; D013213:Starch; D003094:Collagen