靜電紡絲製備新穎性pH應答共聚高分子螢光纖維之合成、型態及可逆性感測探討

The Novel pH-responsive Luminescent Electrospun Fibers Prepared From Random Copolymers: Synthesis, Morphology and Reversible Sensing Property

洪誌鍵(Chih-Chien Hung)

指導教授 ： 郭霽慶

國立臺北科技大學/工程學院/有機高分子研究所/碩士(2013年)

摘要

本實驗研究含螢光感測pH基團、親水基團、交聯基團之多功能性共聚高分子Poly(HEMA-co-NMA-co-RhBAM)合成及製備成靜電紡絲纖維之感測應用。其中以PHEMA為吸水性佳材料，NMA則為化學交聯能夠使纖維不回溶於水中，RhBAM則是pH應答(在pH>6不放光; pH<6時放橘色螢光)，RhBAM 隨水溶液中的酸含量提高，在螢光光譜上橘色放光波長580 nm強度隨之增強。此合成方式是利用自由基聚合法(Free Radical Polymerization)合成出此不同鏈段比例的共聚高分子(P1和P2之HEMA與NMA比例為10/1和10/3) ，再由靜電紡絲技術，調控不同電紡參數將此共聚高分子製備成奈米纖維，利用場發式掃描電子顯微鏡(FE-SEM)觀察其不同交聯條件下之形態變化，並且探討不同纖維的形態在水中對環境應答(pH)的感測效果以及光物理變化。在本研究中，我們發現到不同鏈段比例的共聚高分子，其感測效率會有所差異；P1纖維優於P2纖維，主要原因是由於P1纖維的NMA比例較少，交聯程度較P2纖維小，故造成纖維膨潤更加明顯，使得PHEMA能吸入較多的含H+水，故提高感測效率；其中P1纖維的感測螢光強度有90倍的提升，而P2纖維只有46 倍的提升。除此之外，此纖維材料對pH環境應答的感測具有可逆性感測的表現，重複感測次數可多達近十次左右。更重要的是由於靜電紡絲有較高比表面積，故纖維在感測效率的表現優於薄膜形式。綜上述之優點，此多功能性靜電紡絲纖維，未來將可應用在過濾膜、生物感測、及感測元件等相關領域方面，有相當大的發展潛力。

關鍵字

靜電紡絲 ； 螢光感測 ； 交聯 ； 可逆性

並列摘要

In this study, we prepared electrospun (ES) fiber from mulifunctional random copolymers of poly(HEMA-co-NMA-co-RhBAM). The moieties of HEMA, NMA and RhBAM were designed to the hydrophilic, chemical cross-linking (to ensure insolubility in aquesous), pH-responsive, respectively. The random copolymers were synthesized by free radical copolymerization of the above three kinds of moieties with the different mole ratio, and then prepared to form ES nanofibers using the different electronspinning parameters. It was observed that the variation of morphologies on different operated conditions from SEM. We explored the pH-responsive and photophysical properties of the ES fibers immersed in aqueous solvent with different pH value. The fluorescent emission of 580 nm was gradually increased with increasing concentration of pH from pH value of 7 to 2 for ES fibers due to the pH-responsive RhBAM moiety. In our study, we discovered the difference of efficiency for sensing on dissimilar ratio of the random copolymers. Due to the enhanced degree of cross-linking with increasing the NMA content, the cross-linked ES fibers of P2 have the unobvious swelling morphology. It resulted in the pH-sensing efficiency of P1 ES fibers are better than that of P2. The fluorescent intensity of P1 ES fiber exhibits around 90-fold enhancement at pH value of 2 while only 46-fold enhancement on P2 ES fiber. In addition, the ES fibers had a significant reversibility for pH-dependence and could be repeated for several times. Moreover, the ES fibers led a much better pH-response on the fiber morphology compared with the corresponding spin-coated film because of their high surface/volume. Above all results show that the multi-functional ES fiber have a potential in relative applications, such as filters, bio-sensor and sensory devices.

並列關鍵字

Electrospinning ； luminescent sensing ； cross-link ； reversible

參考文獻

1. Yarin, A.L., S. Koombhongse, and D.H. Reneker, Taylor cone and jetting from liquid droplets in electrospinning of nanofibers. Journal of Applied Physics, 2001. 90(9): p. 4836.

2. Shin, Y.M., et al., Experimental characterization of electrospinning: the electrically forced jet and instabilities. Polymer, 2001. 42(25): p. 09955-09967.

3. Bhattacharjee, P.K. and G.C. Rutledge, Electrospinning and Polymer Nanofibers: Process Fundamentals. 2011: p. 497-512.

4. Teo, W.E. and S. Ramakrishna, A review on electrospinning design and nanofibre assemblies. Nanotechnology, 2006. 17(14): p. R89-R106.

5. Reneker, D.H., et al., Bending instability of electrically charged liquid jets of polymer solutions in electrospinning. Journal of Applied Physics, 2000. 87(9): p. 4531.