Stimuli-Responsive and Mechanically-Switchable Electrospun Composites

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• 作者：Nandula D. Wanasekara ; David A. Stone ; Gary E. Wnek ; LaShanda T. J. Korley
• 刊名：Macromolecules
• 出版年：2012
• 出版时间：November 27, 2012
• 年：2012
• 卷：45
• 期：22
• 页码：9092-9099
• 全文大小：470K
• 年卷期：v.45,no.22(November 27, 2012)
• ISSN：1520-5835

文摘

We report on a family of electrospun nanocomposites, which are capable of altering their stiffness upon hydration. An electrospun mat of poly(vinyl alcohol) (PVA) was incorporated as the filler in a polymeric matrix consisting of either poly(vinyl acetate) (PVAc) or ethylene oxide鈥揺picholorohydrin copolymer (EO鈥揈PI). The tensile modulus of the EO鈥揈PI-based composites was found to increase significantly upon incorporation of the PVA filler mat, while PVAc-based composites exhibited modulus enhancement only above the matrix glass transition. Materials based on the PVAc matrix and PVA electrospun filler exhibited a reversible reduction of the tensile modulus by a factor of 280 upon exposure to water. In contrast, composites comprised of a rubbery EO鈥揈PI matrix and PVA filler showed a reduction of tensile modulus upon water uptake, but with incomplete restoration when dried. A systematic investigation revealed that the underlying mechanism of mechanical response is related to the matrix鈥揻iller interactions and filler crystallinity. The robust technique of electrospinning allows the tailoring of matrix鈥揻iller interactions in a new series of all-organic composites to achieve desired mechanical response upon exposure to various stimuli.