PEG-N-chitosan and PEG-N,O-chitosan were synthesized via reductive amination and acylation of chitosan, respectively. The structures were confirmed by FTIR and H1NMR. The extents of PEGylation increased with reducing chain lengths of either chitosan (Mv = 137-400 kDa) or poly(ethyelene glycol) (PEG, Mn = 500-2 kDa). Water solubility were easily achieved at degree of substitution (DS) as low as 0.2 for either derivtive whereas the PEG-N,O-chitosan at DS = 1.5 was soluble in organic solvents, including CHCl3, DMF, DMSO and THF. None of the aqueous solutions of PEG-N-chitosan or PEG-N,O-chitosan alone could be electrospun into fibers. Electrospinning of PEG550-N,O-chitosan145 at 25% in DMF produced fibrous structure intermixed with beads. The efficiency of fiber formation and the uniformity of fibers were improved by increasing the solution viscosity using a cosolvent or reducing the solution surface tensions with a non-ionic surfactant. Ultra-fine fibers with diameters ranging from 40 nm to 360 nm and an average diameter of 162 nm were efficiently generated from electrospinning of 15% PEG550-N,O-chitosan145 in 75/25 (v/v) THF/DMF cosolvents with 0.5% Triton X-100TM.
- Electrospinning from organic solutions
- Poly(ethylene glycol) graft
- Water soluble: Organic soluble
ASJC Scopus subject areas
- Polymers and Plastics