TiO2 sol–gel reaction induces nanowrinkling along the surface of electrospun poly(vinyl alcohol) (PVA) nanofibers. Nanowrinkling along nanofibers is influenced by electrospinning voltage, degree of nanofiber crosslinking, and the repetitive immersion of nanofibers in TiO2 precursors. Crosslinked nanofibers are dipped in alternating solutions of titanium tetraisopropoxide (TTIP) and water for up to five cycles. Interestingly, nanowrinkles only form along nanofibers that are spun at 45 kV and treated with three or more cycles of sol–gel precursor. Spectroscopy reveals that more PVA hydroxyl groups populate the nanofiber surface when electrospinning occurs at 45 kV than at 15 kV. In turn, surface PVA hydroxyl groups appear to nucleate TiO2 growth. Scanning probe phase micrographs confirm modulus differences between the attached TiO2 particles and PVA's surface. Those moduli differences result in wrinkling, as TTIP-treated nanofibers undergo repetitive cycles of water swelling and isopropanol deswelling.
Bibliographical noteFunding Information:
Y.P. acknowledges the support from Water Resources Research Institute – North Carolina Sea Grant (WRRI-NCSG)’s graduate research funding. The authors thank Preeti Rawat for her assistance in FTIR measurement. Work from project 14-177 NC with The Nonwovens Institute was featured in this study. This work was performed in part at the Analytical Instrumentation Facility (AIF) at North Carolina State University, which is supported by the State of North Carolina and the National Science Foundation (award number ECCS-1542015). AIF is a member of the North Carolina Research Triangle Nanotechnology Network (RTNN), a site in the National Nanotechnology Coordinated Infrastructure (NNCI).
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All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Organic Chemistry
- Polymers and Plastics
- Materials Chemistry