Authors Fischer, K. ; Spange, St. ; Fischer, S. ; Bellmann, C. ; Adams, J.
Title Probing the surface polarity of native cellulose using genuine solvatochromic dyes
Date 15.07.2002
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 agr (hydrogen bond acidity), beta (hydrogen bond basicity), and pgr * (dipolarity/polarizability). agr, beta, pgr *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 agr, beta and pgr *values. It shows a fairly strong acidity agr and a low dipolarity/polarizability. For the amorphous sections smaller agr and larger pgr * values are observed. The correspondence of the empirical polarity parameters determined has been discussed in relation to results from pyrene fluorescence and zetapotential measurements.
Journal Cellulose 9 (2002) 31-40

Back to list