title: Effect of the molecular mass and degree of substitution of oleoylchitosan on the structure, rheological properties, and formation of nanoparticles.
abstract: Oleoylchitosans (O-chitosans), with different molecular masses and degrees of substitution (DS), were synthesized by reacting chitosan with oleoyl chloride. The FT-IR suggested the formation of an amide linkage between amino groups of chitosan and carboxyl groups of oleic acid. The viscosity of O-chitosan sharply increased with the increase of concentration, whereas that of unmodified chitosan rose only slightly. This increase was stronger as the increase of hydrophobicity (DS) and molecular mass of the polymer. The critical aggregation concentration (CAC) of O-chitosans with DS 5, 11, and 27% were 79.43, 31.6, 10 mg/L, respectively, and the CAC of samples with molecular masses of 20, 38, 300, and 1100 kDa were 50.1, 74.93, 125.9, and 630.9 mg/L, respectively. All of the O-chitosans could reduce surface tension slightly. Nanoparticles were prepared using an O/W emulsification method. Mean diameters of the polymeric amphiphilic nanoparticles of O-chitosans with DS 5 and 11% were around 327.4 and 275.3 nm, respectively.
authors.affiliation: College of Marine Life Science, Ocean University of China, 5 Yu Shan Road, Qingdao 266003, People's Republic of China.
authors.forename: Yan Yan
authors.initials: YY
authors.lastname: Li
authors.forename: Xi Guang
authors.initials: XG
authors.lastname: Chen
authors.forename: Cheng Sheng
authors.initials: CS
authors.lastname: Liu
authors.forename: Dong Su
authors.initials: DS
authors.lastname: Cha
authors.forename: Hyun Jin
authors.initials: HJ
authors.lastname: Park
authors.forename: Chong M
authors.initials: CM
authors.lastname: Lee
mesh_terms: D002236:Carbohydrate Conformation; D048271:Chitosan / Q000737:chemistry*; D008854:Microscopy, Electron; D008970:Molecular Weight; D053758:Nanoparticles / Q000737:chemistry*; D019301:Oleic Acid / Q000737:chemistry; D009844:Oligosaccharides / Q000737:chemistry; D011721:Pyrenes / Q000032:analysis; D012212:Rheology; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D009844:Oligosaccharides; D011721:Pyrenes; D019301:Oleic Acid; D048271:Chitosan; C030984:pyrene