Preparation of cationic amphiphilic cellulose copolymers and their self-assembly behavior

摘要

Novel amphiphilic cationic cellulose copolymers were prepared by grafting the hydrophobic poly(p-dioxanone)(PDO)chains onto hydrophilic quaternized cellulose derivatives(QC).The grafting ring-opening polymerization was performed in ionic liquids 1-N-butyl-3-methylimidazolium chloride(BmimCl),using the 4-dimethylaminopyridine(DMAP)or 1,8-diazabicyclo(5.4.0)undec-7-ene(DBU)as catalyst.By controlling the molar ratios of p-dioxanone monomer and catalyst to QC,the content ratios of PDO to QC in copolymers were adjusted.The chemical structures and physical properties of copolymers were analyzed by FT-IR,1H-NMR,13C-NMR,X-ray diffraction(XRD),and thermal stability(TGA)techniques.The self-assembly behaviors of QC-g-PDO copolymers was characterized by dynamic light scattering(DLS),transmission electron microscopy(TEM)and fluorescence techniques.It was found that the hydrodynamic radiuses of self-assembled nanomicelles were ranged from 110 nm to 246 nm and the critical micelle concentration(CMC)values were in the range of 0.064-0.253 mg/mL,both of which were decreased with increasing of the grafting ratios of PDO in copolymers.Furthermore,the ζ-potentials of micelles were 39.1-45.4 mV,indicating that the surface charge on the micelles were cationic.Therefore,the prepared nanomicelles were potentially and favorably applied in the fields of drug/gene delivery and bioimaging.