Ultra metal ions and pH sensing characteristics of thermoresponsive luminescent electrospun nanofibers prepared from poly(HPBO-co-NIPAAm-co-SA)

Abstract

Novel multifunctional fluorescent electrospun (ES) nanofibers were prepared from random copolymers of poly{2-{2-hydroxyl-4-[5-(acryloxy)hexyloxy]phenyl}benzoxazole}-co-(N-isopropylacrylamide)-co-(stearyl acrylate)} (poly(HPBO-co-NIPAAm-co-SA)) using free-radical polymerization, followed by electrospinning.The moieties of HPBO, NIPAAm, and SA were designed to exhibit zinc ion (Zn 2+ ) and pH sensing, thermoresponsiveness, and physical cross-linking, respectively. The ES nanofibers prepared from the P4 copolymer (1 : 93 : 6 composition ratio for HPBO/NIPAAm/SA), showed ultrasensitivity to Zn 2+ (as low as 10 À8 M) because of the large blue-shifting of 75 nm of the emission maximum and the 2.5-fold enhancement of the emission intensity. Furthermore, the nanofibers exhibited a substantial volume (or hydrophilic-hydrophobic) change during the heating and cooling cycle between 10 C and 40 C, attributed to the low critical solution temperature of the thermoresponsive NIPAAm moiety. Such temperature-dependent variation of the prepared nanofibers under the presence of Zn 2+ or basic conditions led to a distinct on-off switching of photoluminescence. The high surface-to-volume ratio of the prepared ES nanofibers significantly enhanced their sensitivity compared to that of thin films. These results indicated that the prepared multifunctional ES nanofibers could be potentially used in metal ion, pH, and temperature sensing devices.

Pyrene or rhodamine derivative–modified surfaces of electrospun nanofibrous chemosensors for colorimetric and fluorescent determination of Cu 2+ , Hg 2+ , and pH

“…A single-capillary spinneret electrospinning device was employed to produce the ES nanofibers ( Fig. 1), as described in our previous reports [27][28][29][30]. The polymer solution was fed into a metallic needle through syringe pumps (KD Scientific Model 100, USA) at a feed rate of 1 mL h −1 .…”

“…These fluorescent ES nanofibrous membranes can be used as "naked eye" sensors; they have potential applications in multifunctional environmental sensing devices that sense physical phenomena including metal ions and pH levels. However, the described nanofibers were usually fabricated from fluorescent copolymers containing a sensing moiety [30] or blended with a sensing probe [34]. In the present study, we developed a new approach to prepare fluorescent ES nanofibrous chromo-sensors for metal ions and pH levels; this new method involves grafting fluorescent sensing probes onto the surfaces of ES nanofibrous substrates.…”

“…The high surface-to-volume ratio of ES nanofibers has motivated extensive studies on sensory applications [27][28][29][30][31][32][33][34]. Recently, we have prepared various fluorescent sensor-based ES polymer nanofibers for sensing pH levels [27], temperatures [28][29][30], NO gases [31], and metal ions [30,[32][33][34]. For example, novel multifunctional fluorescent ES nanofibers from poly{2-{2-hydroxyl-4-[5-(acryloxy)hexyloxy]phenylbenzoxazole}-co-(N-isopropylacrylamide)-co-(stearylacrylate)} (poly(HPBOco-NIPAAm-co-SA)) exhibited distinct on-off photoluminescence (PL) switching for sensing various pH levels, temperatures, and metal ions [30].…”

“…Recently, we have prepared various fluorescent sensor-based ES polymer nanofibers for sensing pH levels [27], temperatures [28][29][30], NO gases [31], and metal ions [30,[32][33][34]. For example, novel multifunctional fluorescent ES nanofibers from poly{2-{2-hydroxyl-4-[5-(acryloxy)hexyloxy]phenylbenzoxazole}-co-(N-isopropylacrylamide)-co-(stearylacrylate)} (poly(HPBOco-NIPAAm-co-SA)) exhibited distinct on-off photoluminescence (PL) switching for sensing various pH levels, temperatures, and metal ions [30]. Reversible ratiometric fluorescent chromo-sensory ES nanofibers featuring high sensitivity to pH and Fe 3+ were prepared using binary blends of poly(2-hydroxyethyl methacrylate-co-N-methylolacrylamideco-nitrobenzoxadiazolyl derivative) (poly(HEMA-co-NMA-co-NBD)) and a pH/metal-ion sensing probe, a spirolactam rhodamine derivative (SRhBOH) [34].…”

Physicochemical Characterization and Cell Adhesion Evaluation of Poly-ε-Caprolactone/BNNT Nanofibers Produced through Electrospinning Process

“…The huge abundance of these hybrid structures and the possibility to combine different properties of each one assure the continued progress that will make it possible to overcome economic and technical limitations in current technology [1]. extracellular matrices [7], carriers for topical/transdermal drug delivery [8], electrical and optical applications [9,10], sensors and high performance structures [11,12] .…”