本研究以具有高螢光量子產率的芘(pyrene)作為螢光基團，再經由聯胺連接2,4-二羥基苯甲醛，後續與甲基丙烯酸進行酯化反應，合成出以抑制光誘導電子轉移機制的方式探測鋅離子的pyrene-based螢光單體3-hydroxy-4-((E)-(((E)-pyren-1-ylmethylene)hydrazineylidene)methyl)phenyl methacrylate (PHM)，單體結構上的羥基、羰基及兩個氮原子與鋅離子螯合後，螢光強度於最大放射波長500 nm處會表現出明顯的提升。本研究再將螢光單體PHM、可交聯高分子NMA與溫度敏感型高分子NIPAAm透過自由基聚合法(free radical polymerization)共聚成出三種不同單體比例之螢光高分子Poly[(N-isopropylacrylamide)-co-(N-(hydroxymethyl)acrylamide)-co-(3-hydroxy-4-((E)-(((E)-pyren-1-ylmethylene)hydrazineylidene)methyl)phenyl methacrylate)] [poly(NIPAAm-co-NMA-co-PHM), PNNPM]，並藉由靜電紡絲技術將螢光高分子製備成奈米纖維，使其作為固態螢光感測器使用。
螢光高分子PNNPM與螢光單體相同，對鋅離子皆表現出優秀的選擇性、即時性與靈敏度，且從Job’s plot實驗得知兩者皆以1:2的螯合關係與Zn2+形成錯合物，pH值環境測試也顯示出PNNPM能應用於中性酸鹼環境(pH值5-7)，除了在銅、鐵、鋁離子存在時，因受順磁性或與單體中螯合點位的交互作用影響，在其他金屬離子存在下皆呈現出抗干擾性。加熱奈米纖維後，因高分子鏈中NMA的交聯與NIPAAm的存在，其具溶劑抗性與收縮膨潤特性，纖維於溶劑中感測金屬離子時不會溶解，且透過升溫可使纖維收縮而排出Zn2+，達到物理性再生的效果，但由於高溫下收縮的物理作用相較EDTA與Zn2+的交互作用更弱，因此效率低於化學性再生。此外，不論是何種形式與型態的螢光感測器，檢測極限都低於5.92 μM，且雖然高分子纖維態之感測性略差於螢光單體與高分子溶液態之感測性，但因固態螢光感測器(纖維態)具有操作簡便、攜帶便利、體積輕薄、更廣的感測範圍及可重複利用性的優點，使其具有在實際應用中的優秀潛力。

In this study, pyrene was used as the fluorophore and linked with 2,4-dihydroxybenzaldehyde via hydrazine, followed by esterification reaction with methacrylic acid to synthesize the pyrene-based fluorescent monomer 3-hydroxy-4-((E)-(((E)-pyren-1-ylmethylene)hydrazineylidene)methyl)phenyl methacrylate (PHM). PHM detects Zn2+ through inhibition of the photoinduced electron transfer (PET) mechanism, resulting in significant fluorescence enhancement at 500 nm. PHM was subsequently copolymerized with the crosslinkable polymer (NMA) and the temperature-sensitive polymer (NIPAAm) via free-radical polymerization to prepare fluorescent polymers with three different monomer ratios Poly[(N-isopropylacrylamide)-co-(N-(hydroxymethyl)acrylamide)-co-(3-hydroxy-4-((E)-(((E)-pyren-1-ylmethylene)hydrazineylidene)methyl)phenyl methacrylate)] [poly(NIPAAm-co-NMA-co-PHM), PNNPM)]. The polymers were further fabricated into nanofibers by electrospinning for use as solid-state fluorescent sensors.
Both PHM and PNNPM exhibited rapid response, high selectivity and sensitivity toward Zn2+. Job's plot analysis indicated a 1:2 binding stoichiometry with Zn2+, while pH studies demonstrated that PNNPM is suitable for neutral conditions (pH 5–7). Except for Cu2+、Fe3+、Al3+, which interfere through paramagnetic effects or competitive coordination, it exhibits resistance to interference from other metal ions. The incorporation of NMA and NIPAAm endowed the nanofibers with solvent resistance and thermal shrinkage–swelling behavior. Heating enabled physical regeneration of the fibers by promoting Zn2+ release, although its efficiency was lower than chemical regeneration. The detection limits of all sensing systems were below 5.92 μM. Despite slightly lower sensitivity than the fluorescent monomer and polymer solution, the nanofibers provide portability, ease of handling, a wider detection range, and reusability, demonstrating promising potential for practical Zn2+ sensing applications.

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