title: Intermolecular interaction and the extended wormlike chain conformation of chitin in NaOH/urea aqueous solution.
abstract: The intra- and intermolecular interactions of chitin in NaOH/urea aqueous system were studied by a combination of NMR measurements (including (13)C NMR, (23)Na NMR, and (15)N NMR) and differential scanning calorimetry. The results revealed that the NaOH and chitin formed a hydrogen-bonded complex that was surrounded by the urea hydrates to form a sheath-like structure, leading to the good dissolution. The optimal concentration range, in which chitin was molecularly dispersed in NaOH/urea aqueous, was found to investigate the chain conformation in the dilute solution with a combination of static and dynamic light scattering. The weight-average molecular weight (Mw), radii of gyration (⟨Rg⟩z), and hydrodynamic radii (⟨Rh⟩z) values of chitin were determined, and the structure-sensitive parameter (ρ) and persistent length (Lp) were calculated to be >2.0 and ∼30 nm, respectively, suggesting an extended wormlike chain conformation. The visualized images from TEM, cryo-TEM, and AFM indicated that, chitin nanofibers were fabricated from the parallel aggregation of chitin chains in NaOH/urea system. This work would provide a theoretical guidance for constructing novel chitin-based nanomaterials via "bottom-up" method at the molecular level.
authors.affiliation: †Department of Chemistry, Wuhan University, Wuhan 430072, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Fang
authors.affiliation: †Department of Chemistry, Wuhan University, Wuhan 430072, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Duan
authors.affiliation: †Department of Chemistry, Wuhan University, Wuhan 430072, China.
authors.forename: Ang
authors.initials: A
authors.lastname: Lu
authors.affiliation: ‡State Key Laboratory of Magnetic Resonance and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, West No. 30 Xiao Hong Shan, Wuhan 430071, China.
authors.forename: Maili
authors.initials: M
authors.lastname: Liu
authors.affiliation: ‡State Key Laboratory of Magnetic Resonance and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, West No. 30 Xiao Hong Shan, Wuhan 430071, China.
authors.forename: Huili
authors.initials: H
authors.lastname: Liu
authors.affiliation: †Department of Chemistry, Wuhan University, Wuhan 430072, China.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Xu
authors.affiliation: †Department of Chemistry, Wuhan University, Wuhan 430072, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Zhang
mesh_terms: D002686:Chitin / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry*; D012972:Sodium Hydroxide / Q000737:chemistry*; D014508:Urea / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D002686:Chitin; D012972:Sodium Hydroxide; D014508:Urea