Soft Matter 2018-04-11

Determine electrospun morphologies from the properties of protein-polymer solutions

Hao Zhang, Shixia Xi, Yingchun Han, Lunyang Liu, Bo Dong, Zhijie Zhang, Quan Chen, Weihong Min, Qingrong Huang, Yunqi Li, Jingsheng Liu

文献索引：10.1039/C7SM02203D

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摘要

Integrating natural macromolecules, e.g. proteins, is a progressive trend to fabricate biocompatible sub-micrometer fibers with tunable diameters using electrospinning technique. The correlation between solution properties and electrospun morphologies is critical. It is quite clear for synthetic linear polymer solutions but remains uncertain for proteins. Here we report the determination of electrospun morphologies in protein-polymer solutions of poly(ethylene oxide) (PEO) and zein, a storage protein from corn. The viscosity of the zein/PEO mixed solutions can be well described using Lederer-Roegiers equation and decreases with the increase of the fraction of zein. The surface tension sharply decreases above a critical concentration at the saturation of interfacial monolayer. Correspondingly, the electrospun morphologies from bead, bead-fiber coexistence, fiber and ribbon were mapped onto a ternary phase diagram and a viscosity contour plot. Such coupling provides a clear way to determine electrospun morphologies from solution properties. The occurrence of electrospun fibers partially follows two empirical rules, while the critical point revealed from surface tension has the best approximation. The diameters of electrospun fibers (D) were found to have a scaling relationship against concentration, zero-shear viscosity and surface tension of solutions. The comparison of these scaling exponents with those from typical polymer solutions is discussed. It suggests that the aqueous ethanol has different solvent qualities to zein and PEO, resulting in the irregular shape in the phase diagram that correlates solution properties and electrospun morphologies.