Effect of annealing‐induced interfacial demixing on crystallization of PEO confined in coaxial electrospun nanofibers

Abstract

Glassy polymer nanofibers with spatially confined poly(ethylene oxide) (PEO) were fabricated by coaxial electrospinning of PEO with polyacrylonitrile (PAN) or polystyrene. The effect of melt-annealing on the crystallization behavior of the confined PEOs was studied using differential scanning calorimetry. It is found that the crystallization behavior of the confined PEOs varies with annealing temperature (T a ), annealing time (t a ), and molecular weight of PEO. Notably, it is observed that the crystallization temperature (T c ) and melting temperature (T m ) of PEO increase with prolongation of t a , for PEO600K/PAN and PEO2K/PAN coaxial electrospun fibers. This phenomenon can be interpreted by the annealing-induced demixing at the core-sheath interface. After the coaxial electrospinning, the core and sheath of the PEO/PAN coaxial fibers are partially compatible due to the miscible solvents used for the core and sheath polymers. Upon annealing, demixing occurs at the core-sheath interface, leading to improved crystallizability of PEO.In the present work, coaxial electrospun fibers with poly(ethylene oxide) (PEO) confined within the glassy polyacrylonitrile (PAN) or polystyrene (PS) sheath were fabricated using different Additional Supporting Information may be found in the online version of this article.

Effect of spinning solvent on crystallization behavior of confined polymers in electrospun nanofibers

“…Ye et al 35 investigated the crystallization behavior of poly(1,4-butylene adipate) (PBA) in PS/PBA blend electrospun fiber. Zou et al 36,37 studied the crystallization behavior of PEO/poly(L-lactide)/PLLA core-shell electrospun fiber where PEO was present as the core material. The nanosized diameter of nanofibers can also significantly affect the chain packing arrangements of polymers.…”