Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
Langmuir. 2012 Apr 3;28(13):5834-44. doi: 10.1021/la300049j. Epub 2012 Mar 22.
We report on the synthesis of poly(vinyl alcohol) (PVA)-silica hybrid nanofibers via sol-gel electrospinning. Silica is synthesized through acid catalysis of a silica precursor (tetraethyl orthosilicate (TEOS) in ethanol-water), and fibers are obtained by electrospinning a mixture of the silica precursor solution and aqueous PVA. A systematic investigation on how the amount of TEOS, the silica-PVA ratio, the aging time of the silica precursor mixture, and the solution rheology influence the fiber morphology is undertaken and reveals a composition window in which defect-free hybrid nanofibers with diameters as small as 150 nm are obtained. When soaked overnight in water, the hybrid fibers remain intact, essentially maintaining their morphology, even though PVA is soluble in water. We believe that mixing of the silica precursor and PVA in solution initiates the participation of the silica precursor in cross-linking of PVA so that its -OH group becomes unavailable for hydrogen bonding with water. FTIR analysis of the hybrids confirms the disappearance of the -OH peak typically shown by PVA, while formation of a bond between PVA and silica is indicated by the Si-O-C peak in the spectra of all the hybrids. The ability to form cross-linked nanofibers of PVA using thermally stable and relatively inert silica could broaden the scope of use of these materials in various technologies.
我们通过溶胶-凝胶静电纺丝法报告了聚（聚乙烯醇）（PVA）-二氧化硅杂化纳米纤维的合成。通过酸催化二氧化硅前体（四乙氧基硅烷（TEOS）在乙醇-水中）合成二氧化硅，并且通过静电纺丝二氧化硅前体溶液和水 PVA 的混合物获得纤维。系统研究了 TEOS 的量、二氧化硅-PVA 比、二氧化硅前体混合物的老化时间以及溶液流变性如何影响纤维形态，并揭示了一个组成窗口，在此窗口中可以获得无缺陷的直径小至 150nm 的杂化纳米纤维。当在水中浸泡一整夜时，即使 PVA 可溶于水，杂化纤维仍保持完整，基本上保持其形态。我们相信，在溶液中混合二氧化硅前体和 PVA 会引发二氧化硅前体参与 PVA 的交联，从而使 PVA 的-OH 基团无法与水形成氢键。杂化物的 FTIR 分析证实了 PVA 通常显示的-OH 峰的消失，而在所有杂化物的光谱中，PVA 和二氧化硅之间形成键的 Si-O-C 峰表明形成了键。使用热稳定和相对惰性的二氧化硅形成交联纳米纤维的能力可能会拓宽这些材料在各种技术中的使用范围。
