Publication Details (including relevant citation information):
Antonio Martínez-Richa, Carbohydrate Polymers, 87 3 2129-2136 (2012)
Z-average root mean square end-to-end distance <ro2>z1/2 and radius of gyration <so2>z1/2 for 13 samples of O-(2-hydroxyethyl)cellulose (HEC) of different molecular weights were derived from Gel Permeation Chromatography and intrinsic viscosity measurements with water as a solvent. At 40° C and pH = 4.5, contraction of chain dimensions is observed, compared with the sizes observed under neutral conditions at room temperature. The effect is lower for samples with higher molecular weights. Values of <ro2>40/DPz also indicate that chain flexibility increases at higher temperature and acidic conditions. From the analysis of molecular weight dependence of <so2> z1/2, Flory exponent u was derived at 40° C and pH = 4.5. A value of u = 0.70 ± 0.02 was recorded, which indicates that a relatively stiff chain is present under these conditions. Finally, different equations to calculate persistence length Lp were evaluated. Values in the range of 260-400 Ǻ were derived for persistence length. Implications of chain conformation in the enzymatic action of cellulases are also discussed.