新型螢光共聚高分子合成及其多功能環境感測器的應用

Abstract

本研究透過不同的螢光感測小分子，設計出一系列構築單體類似，具有多功能感測之螢光共聚高分子。包括(1)具備pH值、Hg2+感測及分離應用的無規則共聚高分子Poly(HEMA-co-NMA-co-RhBN2AM); (2)具備pH值、環境溫度及Hg2+感測應用的無規則共聚高分子Poly(NIPAAm-co-NMA-co-RhBN2AM); (3)具備pH值、環境溫度、Cu2+及Hg2+感測應用的三嵌段無規則共聚高分子P(NIPAAm-co-NAAP)-b-PNMA-b-P(NIPAAm-co-NAAP)及P(NIPAAm-co-RhBN2AM)-b-PNMA-b-P(NIPAAm-co-RhBN2Am)。其中2-Hydroxyethyl methacrylate (HEMA)為高度吸水性材料，N-Isopropylacrylamide (NIPAAm)為吸水性及溫度感測材料，N-methylolacrylamide (NMA)提供化學交聯，以上述單體構築不同比例的高分子主鏈，搭配上具備金屬離子選擇性的螢光感測單體，RhBN2AM (pH值、Hg2+感測)橘紅色螢光放光基團，NAAP(Cu2+感測)螢光變色(綠光藍光)基團。將上述(1)(2)的螢光共聚高分子，分別以靜電紡絲加工技術，製備成能具有pH值、環境溫度及Hg2+感測的多功能新穎性奈米纖維，並藉由螢光的放光強度達到環境感測的目的。而三嵌段螢光共聚高分子(3)則可以應用於水溶液中pH值、環境溫度、Cu2+及Hg2+感測。相較於傳統螢光化學感測器大部份只能應用於有機溶液中的金屬離子感測，本研究結果顯示，此一系列新型化學螢光感測器透過高分子鏈段中NMA的化學交聯，能夠穩定奈米纖維結構，改善其在水溶液中之感測能力、重複使用性，而三嵌段螢光共聚高分子更能夠直接應用於水溶液中的金屬離子感測。綜上所述，此系列具金屬離子(Hg2+、Cu2+)、溫度及pH值感測之新型螢光化學感測器，具肉眼即可判定的螢光之開關表現，且奈米纖維膜更具備金屬離子感測、分離及可重複使用性，未來在生物及環境感測元件等相關領域，具相當大的發展潛力。

A series of novel multifunctional fluorescent chemosensors were based on (1) Poly(HEMA-co-NMA-co-RhBN2AM) random copolymers exhibited high sensitivity of pH, and Hg2+; (2) Poly(NIPAAm-co-NMA-co-RhBN2AM) random copolymers showed the properties of pH, Hg2+, and temperature sensing; (3) the triblock random copolymers, P(NIPAAm-co-NAAP)-b-PNMA-b-P(NIPAAm-co-NAAP) and P(NIPAAm-co-RhBN2AM)-b-PNMA-b-P(NIPAAm-co-RhBN2Am) had pH, Hg2+, Cu2+, and temperature sensing properties. The 2-Hydroxyethyl methacrylate (HEMA) (a highly hydrophilic material), N-Isopropylacrylamide (NIPAAm) (a hydrophilic and thermos-sensitivity material), N-methylolacrylamide (NMA) (a thermo cross-linkable material), RhBN2AM (a pH, and Hg2+-sensing probe with red fluorescence on/off switchable properties), and NAAP (a Cu2+-sensing probe with fluorescence colors changed from green to blue). Moreover, fluorescent chemosensory filter membranes composed of electrospun (ES) nanofibers of (1), and (2) were prepared by using a single-capillary spinneret, they exhibited multi-sensing properties of pH, Hg2+, and temperature. Especially, the fluorescent chemosensory filter membranes were reusable which was due to the thermo cross-linking moiety (NMA) could maintain the cylindrical shapes of ES nanofibers. In addition, the triblock random copolymers, P(NIPAAm-co-NAAP)-b-PNMA-b-P(NIPAAm-co-NAAP) and P(NIPAAm-co-RhBN2AM)-b-PNMA-b-P(NIPAAm-co-RhBN2Am) improved the water solubility of fluorescent probe. Therefore, the novel multifunctional fluorescent chemosensors with fluorescence on/off switchable properties can be used as “naked-eye” sensors and have considerable potential of applications in environment sensing devices.