Alginate–PolyethyleneOxide Blend Nanofibersand the Role of the Carrier Polymer in Electrospinning.

Wepresent here a systematic investigation to understand why aqueoussodium alginate can only be electrospun into fibers through a blendwith another polymer; specifically, polyethylene oxide (PEO). We seekto examine and understand the role of PEO as the “carrier polymer”.The addition of PEO favorably reduces electrical conductivity andsurface tension of the alginate solution, aiding in fiber formation.While PEO has the ability to coordinate through its ether group (−COC−)with metal cation like the sodium cation of sodium alginate, we demonstratein this study using PEO as well as polyvinyl alcohol (PVA) that coordinationmay have little effect on electrospinnability. More importantly, weshow that PEO as carrier polymer provides molecular entanglement thatis required for electrospinning. Since the selected carrier polymerprovides the necessary entanglement, this carrier polymer must beelectrospinnable, entangled and of a high molecular weight (more than600 kDa for PEO). On the basis of these requirements, we stipulatethat the PEO–PEO interaction of the high molecular-weight entangledPEO is key to “carrying” the alginate from solutionto fibers during electrospinning. Further, using the resulting understandingof the role of PEO, we were able to increase the alginate concentrationby employing a higher molecular-weight PEO: up to 70 wt % alginateusing 2000 kDa PEO and, with, the addition of Triton X-100 surfactant,up to 85 wt % alginate, higher than previously reported. [ABSTRACT FROM AUTHOR]