Nanofibers with Very Fine Core-Shell Morphology from Anisotropic Micelle of Amphiphilic Crystalline-Coil Block Copolymer
作者：F. Y. Zhai, W. Huang, G. Wu, X. K. Jing, M. J. Wang, S. C. Chen*, Y. Z. Wang, I. J. Chin, Y. Liu
關鍵字：single spinneret electrospinning, core-shell nanofiber, crystalline-coil copolymer, anisotropic micelle
論文來源：期刊
具體來源：ACS Nano
發表時間：2013年
A novel and facile strategy, combining anisotropic
micellization of amphiphilic crystalline-coil copolymer in water and
re-assembly during single spinneret electrospinning, was developed for preparing nanofibers with very fine core-shell structure. Polyvinyl alcohol (PVA) and polyethylene glycol-block-poly(p-dioxanone) (PEG-b-PPDO)
were used as the shell and the crystallizable core layer,
respectively. The core-shell structure could be controllably produced by
altering concentration of PEG-b-PPDO, and the chain length
of the PPDO block. The morphology of the nanofibers was investigated by Transmission Electron
Microscope (TEM) and Scanning Electron Microscope (SEM). X-ray rocking curve measurements were performed to investigate the degree of ordered alignment of the PPDO
crystalline lamellae in the
nano fiber. The results suggested that the morphology of
nano particles in spinning solution plays very important role in determining
the phase separation of nano fibers. The amphiphilic PEG-b-PPDO copolymer self assembled
into star anise-nano aggregates in water solution induced by the
crystallization of PPDO blocks. When incorporated with PVA, the interaction
between PVA and PEG-b-PPDO caused a morphological transition of the nano
aggregates from star anise to small flake. For flake-like particles, their flat
surface is in favor of compact stacking of PPDO crystalline lamellae and
interfusion of amorphous PPDO in the core of nano fibers, leading to a
relatively ordered alignment of PPDO crystalline lamellae and well defined
core-shell phase separation. However, for star anise-like nano aggregates, their multi-branched
morphology may inevitably prohibit the compact interfusion of PPDO phase,
resulting in a random micro-phase separation.