The dynamics of chitosan (CS) in solution have been studied by 1 H NMR relaxation [longitudinal (T 1 ) and transverse
(T 2 ) relaxation times and NOE] as a function of the degrees of acetylation (DA, 1 - 70) and polymerization (DP,
10 - 1200), temperature (278 - 343 K), concentration (0.1 - 30 g/L), and ionic strength (50 - 400 mM). This analysis
points to CS as a semirigid polymer with increased ﬂexibility at higher DA in agreement with reduced electrostatic
repulsions between protonated amino groups.