Electrospun Nanofiber Mat of α-1,3-Glucan Butenoate and Its Surface Modification via Thiol-Ene Reaction

α-1,3-glucan ester with carbon-carbon double bonds (C=C), namely, α-1,3-glucan butenoate (α13GB) was synthesized from 3-butenoic acid and trifluoroacetic anhydride. Nonwoven nanofiber mat was successfully prepared by electrospinning α13GB / HFIP solution. α13GB had many reactive vinyl groups in its ester groups that could attribute to thiol-ene reaction, making it possible to modify the nanofiber mat surface by one step chemical functionalization using thiol-ene reactions. The surface of nanofiber mat was modified with 1H,1H,2H,2H-perfluorodecanethiol (PFD) or 3-mercapto-1,2-propanediol (MPD) via thiol-ene reactions. Attenuated total reflection-Fourier-transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX) analyses revealed that the surface of the nanofiber mat was successfully modified with these thiol compounds. The water contact angle (WCA) of the surface of each nanofiber mat was measured to evaluate its wettability changes, and indicated the mat modified with PFD showed super-hydrophobicity (WCA>150̊). Furthermore, the morphology of nanofiber was successfully maintained even after modification by adjusting reaction time.