TY - JOUR
T1 - Macromolecular conformation of chitosan in dilute solution
T2 - A new global hydrodynamic approach
AU - Morris, Gordon A.
AU - Castile, Jonathan
AU - Smith, Alan
AU - Adams, Gary G.
AU - Harding, Stephen E.
PY - 2009/5/16
Y1 - 2009/5/16
N2 - Chitosans of different molar masses were prepared by storing freshly prepared samples for up to 6 months at either 4, 25 or 40 °C. The weight-average molar masses, Mw and intrinsic viscosities, [η] were then measured using size exclusion chromatography coupled to multi-angle laser light scattering (SEC-MALLS) and a "rolling ball" viscometer, respectively. The solution conformation of chitosan was then estimated from:(a)the Mark-Houwink-Kuhn-Sakurada (MHKS) power law relationship [η] = kMw a and(b)the persistence length, Lp calculated from a new approach based on equivalent radii [Ortega, A., & Garcia de la Torre, J. (2007). Equivalent radii and ratios of radii from solution properties as indicators of macromolecular conformation, shape, and flexibility. Biomacromolecules, 8, 2464-2475]. Both the MHKS power law exponent (a = 0.95 ± 0.01) and the persistence length (Lp = 16 ± 2 nm) are consistent with a semi-flexible rod type (or stiff coil) conformation for all 33 chitosans studied. A semi-flexible rod conformation was further supported by the Wales-van Holde ratio, the translational frictional ratio and sedimentation conformation zoning.
AB - Chitosans of different molar masses were prepared by storing freshly prepared samples for up to 6 months at either 4, 25 or 40 °C. The weight-average molar masses, Mw and intrinsic viscosities, [η] were then measured using size exclusion chromatography coupled to multi-angle laser light scattering (SEC-MALLS) and a "rolling ball" viscometer, respectively. The solution conformation of chitosan was then estimated from:(a)the Mark-Houwink-Kuhn-Sakurada (MHKS) power law relationship [η] = kMw a and(b)the persistence length, Lp calculated from a new approach based on equivalent radii [Ortega, A., & Garcia de la Torre, J. (2007). Equivalent radii and ratios of radii from solution properties as indicators of macromolecular conformation, shape, and flexibility. Biomacromolecules, 8, 2464-2475]. Both the MHKS power law exponent (a = 0.95 ± 0.01) and the persistence length (Lp = 16 ± 2 nm) are consistent with a semi-flexible rod type (or stiff coil) conformation for all 33 chitosans studied. A semi-flexible rod conformation was further supported by the Wales-van Holde ratio, the translational frictional ratio and sedimentation conformation zoning.
KW - Chitosan
KW - Equivalent radii
KW - Intrinsic viscosity
KW - Molar mass
KW - Molar weight
KW - Sedimentation coefficient
KW - Semi-flexible rod conformation
UR - http://www.scopus.com/inward/record.url?scp=63149194922&partnerID=8YFLogxK
UR - https://www.journals.elsevier.com/carbohydrate-polymers/
U2 - 10.1016/j.carbpol.2008.11.025
DO - 10.1016/j.carbpol.2008.11.025
M3 - Article
AN - SCOPUS:63149194922
VL - 76
SP - 616
EP - 621
JO - Carbohydrate Polymers
JF - Carbohydrate Polymers
SN - 0144-8617
IS - 4
ER -