本研究成功設計並合成一種新型羅丹明B衍生物螢光單體RM，並結合自由基聚合法合成一系列具刺激響應與可交聯特性的螢光共聚高分子poly(NIPAAm-co-NMA-co-RM)(簡稱PNNRM)。利用羅丹明螺內醯胺結構特有的開閉環光學轉變作為感測機制。在初始狀態下，該高分子呈現無色且不具螢光的閉環狀態；當環境中引入具硬酸特性的鋁離子時，單體與鋁離子會發生螯合配位，誘導螺環結構開啟，並有效抑制分子內光誘導電子轉移（PET）效應，在584 nm處釋放出強烈的增強型螢光響應。為開發具可攜性與重複使用性的固態感測材料，本研究透過旋轉塗佈與靜電紡絲技術，分別將高分子溶液加工製備成連續相薄膜與多孔奈米纖維。實驗結果顯示，螢光高分子PNNRM對Al3+具有優異的選擇性與即時偵測能力，並經由Job’s plot證實其與Al3+以 1：2 的計量比形成穩定的螯合錯合物。酸鹼值測試表明，該感測材料的最佳運作環境為pH 6~9。光學性質對比顯示，儘管奈米纖維態的感測靈敏度略遜於溶液態，但固態材料具備操作簡便、便於攜帶以及可透過EDTA脫螯合實現重複利用等優勢，展現出應用於環境中鋁離子固態現場即時檢測的優異潛力。

In this study, Rhodamine B derivative fluorescent monomer (RM) was successfully designed and synthesized, followed by the preparation of a series of stimulus-responsive and crosslinkable fluorescent copolymers, poly(NIPAAm-co-NMA-co-RM) (PNNRM), via free-radical polymerization. The sensing mechanism leverages the characteristic spiro-lactam ring open/close optical transition of the Rhodamine unit. In its initial state, the copolymer remains colorless and non-fluorescent due to the closed-ring conformation. Upon the introduction of Al3+, a hard acid, chelation-coordination between the monomer and Al3+ induces spiro-ring opening while effectively suppressing the photoinduced electron transfer (PET) process, giving rise to a strong fluorescence enhancement at 584 nm .
To develop portable and reusable solid-state sensing platforms, PNNRM solutions were processed into thin films and porous nanofibers via spin-coating and electrospinning, respectively. Experimental results demonstrate that PNNRM exhibits high selectivity and real-time detection capability toward Al3+, with a 1:2 binding stoichiometry confirmed by Job’s plot analysis. The optimal operational environment was determined to be within pH 6–9. Although the sensing sensitivity of the nanofibrous state is slightly lower than that in the solution state, the solid-state materials offer distinct advantages including operational simplicity, portability, and reusability through EDTA-mediated dechelation, highlighting their excellent potential for on-site, real-time solid-state detection of environmental aluminum ions.

(1) Vlasak, T.; Dujlovic, T.; Barth, A. Aluminum exposure and cognitive performance: A meta-analysis. Science of The Total Environment 2024, 906, 167453.
(2) Klotz, K.; Weistenhöfer, W.; Neff, F.; Hartwig, A.; van Thriel, C.; Drexler, H. The Health Effects of Aluminum Exposure. Dtsch. Arztebl. Int. 2017, 114 (39), 653–+.
(3) Yang, Q.; Li, J.; Wang, X.; Peng, H.; Xiong, H.; Chen, L. Strategies of molecular imprinting-based fluorescence sensors for chemical and biological analysis. Biosensors and Bioelectronics 2018, 112, 54–71.
(4) Kasha, M. Characterization of electronic transitions in complex molecules. Discussions of the Faraday society 1950, 9, 14–19.
(5) Lakowicz, J. R. Principles of fluorescence spectroscopy; Springer, 2006.
(6) Bai, L.; Zhang, M.; Huang, Y.; Wang, C.; Bai, Y. A furo-fused coumarin dye with large Stokes shift and intensive emission intensity: its design, synthesis, characterizaiton, optical properties and solvatochromic applications. Journal of Molecular Structure 2025, 1338, 142319.
(7) Valeur, B.; Berberan-Santos, M. N. Molecular Fluorescence. 2012.
(8) Shivani, K.; Padhy, A. A.; Sahoo, S.; Kumari, V.; Mishra, P. Spectroscopic methods to detect and analyze protein oligomerization, aggregation, and fibrillation. Elsevier, 2023; pp 415–458.
(9) Principles of Fluorescence Spectroscopy. 2006.
(10) Khanna, C.; Silakari, P. A comprehensive review on chemosensor design: Strategies, sensing mechanisms, and functional applications. Phosphorus, Sulfur, and Silicon and the Related Elements 2026, 201 (3), 211–228.
(11) Sharma, S. K.; Sehgal, N.; Kumar, A. Biomolecules for development of biosensors and their applications. Current Applied Physics 2003, 3 (2-3), 307–316.
(12) Guo, C.; Sedgwick, A. C.; Hirao, T.; Sessler, J. L. Supramolecular fluorescent sensors: An historical overview and update. Coordination Chemistry Reviews 2021, 427, 213560.
(13) Mattison, R. L.; Bowyer, A. A.; New, E. J. Small molecule optical sensors for nickel: The quest for a universal nickel receptor. Coordination Chemistry Reviews 2020, 425, 213522.
(14) Alshareef, F. M.; Algethami, J. S.; Alhamami, M. A. M.; Alosaimi, E. H.; Al-Saidi, H. M.; Khan, S. Recent advancement in organic fluorescent and colorimetric chemosensors for the detection of Al3+ ions: A review (2019–2024). Journal of Environmental Chemical Engineering 2024, 12 (5), 114110.
(15) Naithani, S.; Dubey, R.; Goswami, T.; Thetiot, F.; Kumar, S. Optical detection strategies for Ni ion using metal–organic chemosensors: from molecular design to environmental applications. Dalton Transactions 2024, 53 (43), 17409–17428.
(16) Lu, X.; Wu, M.; Wang, S.; Qin, J.; Li, P. An AIE/PET-based fluorescent probe for Zn2+/Al3+ detection and its application in fluorescence-assisted diagnosis for prostate cancer. Dyes and Pigments 2022, 203, 110372.
(17) Pandey, R.; Kumar, A.; Xu, Q.; Pandey, D. S. Zinc, copper and cadmium complexes as fluorescent chemosensors for cations. Dalton Transactions 2020, 49 (3), 542–568.
(18) Tarai, A.; Li, Y.; Liu, B.; Zhang, D.; Li, J.; Yan, W.; Zhang, J.; Qu, J.; Yang, Z. A review on recognition of tri-/tetra-analyte by using simple organic colorimetric and fluorometric probes. Coordination Chemistry Reviews 2021, 445, 214070.
(19) Wu, L.; Huang, C.; Emery, B. P.; Sedgwick, A. C.; Bull, S. D.; He, X.-P.; Tian, H.; Yoon, J.; Sessler, J. L.; James, T. D. Förster resonance energy transfer (FRET)-based small-molecule sensors and imaging agents. Chemical Society Reviews 2020, 49 (15), 5110–5139.
(20) Liu, J.; Qian, Y. A novel naphthalimide-rhodamine dye: Intramolecular fluorescence resonance energy transfer and ratiometric chemodosimeter for Hg 2+ and Fe 3+. Dyes and Pigments 2017, 136, 782–790.
(21) Tian, H.; Sedgwick, A. C.; Han, H.-H.; Sen, S.; Chen, G.-R.; Zang, Y.; Sessler, J. L.; James, T. D.; Li, J.; He, X.-P. Fluorescent probes for the imaging of lipid droplets in live cells. Coordination Chemistry Reviews 2021, 427, 213577.
(22) Zhou, Z.; Niu, W.; Lin, Z.; Cui, Y.; Tang, X.; Li, Y. A novel “turn-off” fluorescent sensor for Al3+ detection based on quinolinecarboxamide-coumarin. Inorganic Chemistry Communications 2020, 121, 108168.
(23) Wang, Y.; Wang, X.; Ma, W.; Lu, R.; Zhou, W.; Gao, H. Recent Developments in Rhodamine-Based Chemosensors: A Review of the Years 2018–2022. Chemosensors 2022, 10 (10), 399.
(24) Kim, H. N.; Lee, M. H.; Kim, H. J.; Kim, J. S.; Yoon, J. A new trend in rhodamine-based chemosensors: application of spirolactam ring-opening to sensing ions. Chemical Society Reviews 2008, 37 (8), 1465.
(25) Udhayakumari, D.; Inbaraj, V. A Review on Schiff Base Fluorescent Chemosensors for Cell Imaging Applications. Journal of Fluorescence 2020, 30 (5), 1203–1223.
(26) Al Zoubi, W.; Ko, Y. G. Organometallic complexes of Schiff bases: Recent progress in oxidation catalysis. Journal of Organometallic Chemistry 2016, 822, 173–188.
(27) Gupta, V. K.; Singh, A. K.; Kumawat, L. K. Thiazole Schiff base turn-on fluorescent chemosensor for Al3+ ion. Sensors and Actuators B: Chemical 2014, 195, 98–108.
(28) Wang, K.; Amin, K.; An, Z.; Cai, Z.; Chen, H.; Chen, H.; Dong, Y.; Feng, X.; Fu, W.; Gu, J. Advanced functional polymer materials. Materials Chemistry Frontiers 2020, 4 (7), 1803–1915.
(29) Musarurwa, H.; Tavengwa, N. T. Stimuli-responsive polymers and their applications in separation science. Reactive and Functional Polymers 2022, 175, 105282.
(30) Kim, Y.-J.; Matsunaga, Y. T. Thermo-responsive polymers and their application as smart biomaterials. Journal of Materials Chemistry B 2017, 5 (23), 4307–4321.
(31) Wu, Y.; Tao, Q.; Xie, J.; Lu, L.; Xie, X.; Zhang, Y.; Jin, Y. Advances in Nanogels for Topical Drug Delivery in Ocular Diseases. Gels 2023, 9 (4), 292.
(32) Chuang, W.-J.; Chiu, W.-Y.; Tai, H.-J. Temperature-dependent conductive composites: poly(N-isopropylacrylamide-co-N-methylol acrylamide) and carbon black composite films. Journal of Materials Chemistry 2012, 22 (38), 20311.
(33) Rashid, T. U.; Gorga, R. E.; Krause, W. E. Mechanical Properties of Electrospun Fibers—A Critical Review. Advanced Engineering Materials 2021, 23 (9), 2100153.
(34) Jeong, J. S.; Moon, J. S.; Jeon, S. Y.; Park, J. H.; Alegaonkar, P. S.; Yoo, J. B. Mechanical properties of electrospun PVA/MWNTs composite nanofibers. Thin Solid Films 2007, 515 (12), 5136–5141.
(35) Kim, B.; Kim, J.; Kim, C.; Kang, Y.; Park, H.; Won, J. J. Polym. Sci., Part B: Polym. Phys. 1999.
(36) Bhardwaj, N.; Kundu, S. C. Electrospinning: A fascinating fiber fabrication technique. Biotechnology Advances 2010, 28 (3), 325–347.
(37) Eda, G.; Shivkumar, S. Bead‐to‐fiber transition in electrospun polystyrene. Journal of Applied Polymer Science 2007, 106 (1), 475–487.
(38) Sukigara, S.; Gandhi, M.; Ayutsede, J.; Micklus, M.; Ko, F. Regeneration of Bombyx mori silk by electrospinning—part 1: processing parameters and geometric properties. Polymer 2003, 44 (19), 5721–5727.
(39) Zeng, J.; Haoqing, H.; Schaper, A.; Wendorff, J. H.; Greiner, A. Poly-L-lactide nanofibers by electrospinning – Influence of solution viscosity and electrical conductivity on fiber diameter and fiber morphology. e-Polymers 2003, 3 (1).
(40) Greiner, A.; Wendorff, J. H. Electrospinning: A Fascinating Method for the Preparation of Ultrathin Fibers. Angewandte Chemie International Edition 2007, 46 (30), 5670–5703.
(41) Zargham, S.; Bazgir, S.; Tavakoli, A.; Rashidi, A. S.; Damerchely, R. The Effect of Flow Rate on Morphology and Deposition Area of Electrospun Nylon 6 Nanofiber. Journal of Engineered Fibers and Fabrics 2012, 7 (4), 155892501200700.
(42) Wang, C.; Chien, H.-S.; Hsu, C.-H.; Wang, Y.-C.; Wang, C.-T.; Lu, H.-A. Electrospinning of Polyacrylonitrile Solutions at Elevated Temperatures. Macromolecules 2007, 40 (22), 7973–7983.
(43) Casper, C. L.; Stephens, J. S.; Tassi, N. G.; Chase, D. B.; Rabolt, J. F. Controlling Surface Morphology of Electrospun Polystyrene Fibers:  Effect of Humidity and Molecular Weight in the Electrospinning Process. Macromolecules 2004, 37 (2), 573–578.
(44) Zohreh Mirjalili, S.; Chavoshi, F.; Amini, M.; Zahratamiji; Kobarfard, F.; Shirangi, M. Development of a high-performance liquid chromatography using rhodamine B hydrazide as the derivatization reagent for determination of β propiolactone residues in inactivated COVID-19 vaccines. Journal of Chromatography B 2024, 1244, 124241.
(45) Jeong, J.; Rao, B.; Son, Y. Rhodamine-chloronicotinaldehyde-based "OFF-ON" chemosensor for the colorimetric and fluorescent determination of Al3+ ions. Sens. Actuator B-Chem. 2015, 208, 75–84.