The dimensional characterization of ethylcellulose (ECx, x = 3.0 or 2.5) with a weight-averaged molar mass (Mw) of 6.32 × 103 to 3.83 × 105 g mol−1 and narrow dispersity (Mw/Mn < 1.22) was performed in tetrahydrofuran (THF) at 25 °C using static light scattering, small-angle X-ray scattering, and intrinsic viscosity measurements. Eleven fully substituted EC3.0 samples were prepared by the ethylation of EC2.5 in THF and fractionated by recycling preparative SEC in CHCl3. Eight EC2.5 fractions were obtained similarly. The z-averaged radius of gyration and intrinsic viscosity were measured and analyzed using a wormlike chain model. The Kuhn length, molar mass per contour length, and bead diameter were 23.1 nm, 491 g mol−1 nm−1, and 1.8 nm (EC3.0) and 16.5 nm, 467 g mol−1 nm−1, and 1.1 nm (EC2.5), respectively. Both are semiflexible, and x affects the global stiffness and hydrodynamic radius but not the local conformation (monomer length ≈ 0.50 nm).
- Kenji Fukuda
- Moriya Kikuchi
- Seigou Kawaguchi
