An amphiphilic random copolypeptide

poly(-benzyl-L-glutamate-co-N-(2-hydroxyethyl)-L-glutamine](PBHG)

was modified from hydrophobic poly(-benzyl-L-glutamate)(PBLG) to improve hydrophilicity and applied to electrospin into ultrafine fibers.The molecular structure was confirmed by Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance spectroscopy (1H-NMR).The effects of solvent type and PBHG concentration on the properties of spinning solutions were investigated by measuring surface tension

viscosity and conductivity of the solutions.The morphologies of electrospun fibers were observed by scanning electron microscope.The hydrophilicity and cell proliferation ability of PBHG electrospun fibrous mats were also evaluated by water immersion and MTT assay

respectively.It was found that PBHG takes rigid -helix conformation and tends to self-orientate in trichloromethane (TCM) and tetrahydrofuran (THF) from which micron or submicron fibers could be electrospun.The fibers electrospun from PBHG/TCM solutions have poor quality due to large surface tension

high viscosity and low conductivity of the solutions

whereas those obtained from PBHG/THF solutions have smooth surface and homogeneous diameter.In trifluoroacetic acid (TFA)

PBHG molecules take random coil conformation and physically entangle with each other.The low surface tension

low viscosity and high conductivity of PBHG/TFA solutions are beneficial for electrispinning nano-fibers

but the low volatility of TFA leads to fiber adhesion.It can be alleviated by using TFA/TCM binary mixtures with suitable TFA content as solvent.PBHG electrospun fibers proved to be more hydrophilic than that of PBLG

and could maintain the skeleton in the water without further crosslinking.MTT results confirmed that PBHG fibers are non-cytotoxic and can promote the cell proliferation.