Probing the surface polarity of native celluloses using genuine solvatochromic dyes
Source: Cellulose, Volume 9, Number 1, March 2002 , pp. 31-40(10)
Abstract:The surface polarity of native celluloses has been investigated by the following solvatochromic dyes: dicyano-bis (1,10)-phenanthroline iron (II) Fe(phen)2 (CN)2 (1), bis(4-N,N-dimethylamino)-benzophenone (2), and cou-marine 153 (3). Linear Solvation Energy (LSE) relationships and the UV/Vis data have been used to characterize the surface polarity of different native cellulose batches in terms of the empirical Kamlet–Taft polarity parameters α (hydrogen bond acidity), (hydrogen bond basicity), and * (dipolarity/polarizability). α, , * and calculated Reichardt's E T (30) values are reported for various native and regenerated cellulose samples with different degrees of crystallinity. The degree of crystallinity of the cellulose samples has been determined by X-ray. The microcrystalline environment of cellulose can be exactly parameterized in terms of the α, and * values. It shows a fairly strong acidity α and a low dipolarity/polarizability. For the amorphous sections smaller α and larger * values are observed. The correspondence of the empirical polarity parameters determined has been discussed in relation to results from pyrene fluorescence and zetapotential measurements.
Document Type: Regular Paper
Affiliations: 1: Polymer Chemistry, Institute for Chemistry, Faculty of Science, University of Technology Chemnitz, Strasse der Nationen 62, D-09111 Chemnitz, Germany 2: Polymer Chemistry, Institute for Chemistry, Faculty of Science, University of Technology Chemnitz, Strasse der Nationen 62, D-09111 Chemnitz, Germany E-mail: Stefan.Spange@chemie.tu-chemnitz.de 3: Department of Inorganic Chemistry, Technical University of Freiberg, Leipziger Strasse 29, D-09596 Freiberg, Germany 4: IPF Dresden, Hohe Strasse 6, D-01069 Dresden, Germany 5: Institute of Physical Chemistry, Technical University Clausthal, Arnold-Sommerfeld Strasse 4, D-38678 Clausthal-Zellerfeld, Germany
Publication date: March 1, 2002