Preparation of cellulose-graft-poly(ε-caprolactone) nanomicelles by homogeneous ROP in ionic liquid

Self-associating cellulose-graft-poly(E-caprolactone) (cellulose-g-PCL) copolymers were successfully synthesized via homogeneous ring-opening polymerization (ROP) of E-CL onto softwood dissolved pulp substrate in ionic liquid 1-N-butyl-3-methylimidazolium chloride ([Bmim]Cl). An organic catalyst N,Ndimethylamino-4-pyridine (DMAP) was compared with the traditional metal-based catalyst (Sn(Oct)(2)) as the catalyst of the reaction, and exhibited higher catalytic activity. By controlling the cellulose:ECL feed ratio and reaction temperature, the molecular architecture of the copolymers can be altered, as evidenced by FT-IR. H-1 NMR, C-13 NMR, TGA and XRD. The self-assembly behavior of the copolymers in water was investigated and characterized using fluorescence probe, dynamic light scattering (DLS) and SEM. The results showed that the cellulose-g-PCL copolymers could form nanosized micelles (approximately 20-100 nm) in water, and the micelle size and critical micelle concentration (CMC) can be controlled by varying the grafting ratio of PCL These cellulose-based nanomicelles are expected to be useful in broad application fields. (C) 2012 Elsevier Ltd. All rights reserved.