The design, synthesis, and optimization of excited-state intramolecular proton transfer (ESIPT)-associated dual-emissive aliphatic conductive polymer is one of the very challenging tasks, and has not been reported to date. Herein, aliphatic fluorescent conducting polymers (FCPs) are synthesized by polymerizing N-(monomethylol)acrylamide (MMA), acrylic acid (AA), and in situ-generated 3-N-(monomethylolacrylamido)propanoic acid (NMMAPA). Of different FCPs, the maximum population of heteroatomic nontraditional luminophores, i.e., secondary amide (-CONH), imidol (-CN(OH)), tertiary amide (-CON), and carboxylic acid (-COOH), in FCP4 is supported by the spectroscopic analyses, thermal profiles, fluorescence enhancements, and computational calculations. Thus, further investigations are made on FCP4 to explore the photophysical properties, check the suitability in dual metal ion sensing, and study the proton conductivity. The ESIPT-associated dual light emissions at 436 nm (lambda(em1)) and 573/617 nm (lambda(em2)) originate from FCP4 (amide)/FCP4 (amide)-aggregate and FCP4 (imidol)/FCP4 (imidol)-aggregate, respectively, and are supported by concentration-dependent emissions, time-correlated single photon counting studies, solvent polarity effects, and computational measurements. Regarding this, the high fluorescence quantum yields of 0.68 and 0.18 at lambda(em1) and lambda(em2), respectively, confirmed the ESIPT-associated strong dual emissions of FCP4. The UV spectrum within 264-300 nm, FTIR peak at 2165 cm(-1), binding energies of -CN(OH)/-CN(OH) at 399.0/533.4 eV, and computational studies indicate the coexistence of FCP4 (amide)/FCP4 (amide)-aggregate and FCP4 (imidol)/FCP4 (imidol)-aggregate forms of FCP4. In FCP4, -CONH/-CN(OH)/-CON/-COOH/-CH2OH-associated dipolar and hydrogen-bonding interactions, n-pi* transitions, and N-branching-associated rigidity contribute to ESIPT-associated amide-imidol phototautomerism, aggregation-enhanced emissions, dual light emissions, metal ion sensing, and conductivity. The strong coordinations of Fe(III) and Cr(III) with FCP4 (amide) and FCP4 (imidol), respectively, are supported by spectroscopic, thermal, and computational studies. The strong quenching efficiencies of Fe(III) and Cr(III) are indicated by the very low limits of detection of 0.1142 and 0.0534 ppb, respectively. The I-V and ac impedance spectroscopy data of FCP4 having 0.28 cm thickness and 1.72 cm(2) area indicate high proton conductivities of 3.53 x 10(-5) and 3.22 x 10(-5) S cm(-1) at pH = 7.0 and 8.0, respectively.

The design, synthesis, optimization, and development of an excited-state energy transfer (ESET)-assisted dual-light emission hybrid polymeric sensor are very much challenging, particularly when the polymer is purely aliphatic and bears nonconventional heteroatomic subfluorophores. In this work, aliphatic light-emitting polymers (LEPs) are synthesized from dimethylaminoethyl methacrylate and maleic acid monomers having -C(= O)OCH2-, -N(CH3)(2), and -C(=O)OH/-C(=O)O- subfluorophores. In aliphatic LEPs, hydrogen bond associated strong supramolecular networks facilitate n ->pi* transmissions and dual excitation dual emission. The optimum incorporation of subfluorophores in LEP5 is supported by Fourier transform infrared (FTIR) and nuclear magnetic resonance spectroscopies, thermogravimetric profiles, and aggregation enhanced emission (AEE) studies. Thereafter, the sulfonated graphene oxide (SGO) nanoparticle is incorporated in the optimum LEP5 to fabricate hybrid light-emitting polymers (HLEPs) having increased size/surface area, noncovalent interactions, and electronic distributions. In HLEPs, electron rich polar -C(=O)OH/-C(=O)O- and -SO3H/-SO3- functionalities increase hydrogen bonding and dipole-dipole interactions. Among HLEPs, HLEP3 having the maximum aggregating tendency and emission capacity is optimized by AEE studies and FTIR, Raman, powder X-ray diffraction (PXRD), and thermogravimetric analyses. In the aggregation-associated ESET phenomenon of HLEP3, the SGO nanoparticle acts as an energy acceptor. The ESET-associated single-excitation dual emissions are supported by the absorption and emission maxima of HLEP3-aggregate and HLEP3, respectively; excitation spectra; and average lifetimes in time correlated single photon count studies. The aggregations of HLEP3 are supported by dynamic light scattering (DLS) studies, scanning electron microscopy photomicrographs, and UV-vis spectra. The dual-emission phenomena of HLEP3 and its pH-sensitive subfluorophores -N(CH3)(2), -C(=O)OH/-C(=O)O-, and -SO3H/SO3- are responsible for precise ratiometric pH sensing within 8.0-11.0. The reversibility test and PXRD data of HLEP3 at different pH values indicate the stability of HLEP3 in acidic, neutral, and basic media. The dual-light emissions facilitate rapid sensing and detections of Co(II) and Bi(III) with limits of detection below the WHO-recommended values in both aqueous and nonaqueous media. The strong coordinations of Co(II) and Bi(III) with -C(=O)O-/-SO3H/-SO3- of HLEP3 and HLEP3-aggregate, respectively, are confirmed by UV-vis, FTIR, and Raman spectroscopies along with the DLS measurements. KEYWORDS: dual-emission hybrid polymers, sulfonated-GO nanoparticle, optimum fluorescence emission, ESET and aggregations, reusable M(II/III) sensors, ratiometric dynamic pH sensing

The strategic utilization of hazardous particulate waste in eliminating environmental pollution is an important research hotspot. Herein, abundantly available hazardous solid collagenic waste of leather industry is converted into stable hybrid nanobiocomposite (HNP@SWDC) comprising magnetic hematite nanoparticles (HNP) and solid waste derived collagen (SWDC) via co-precipitation method. The structural, spectroscopic, surface, thermal, and magnetic properties; fluorescence quenching; dye selectivity; and adsorption are explored via microstructural analyzes of HNP@SWDC and dye adsorbed-HNP@SWDC using 1H nuclear magnetic resonance, Raman, ultraviolet-visible, Fourier-transform infrared (FTIR), X-ray photoelectron, and fluorescence spectroscopies; thermogravimetry; field-emission scanning electron microscopy; and vibrating-sample magnetometry (VSM). The intimate interaction of SWDC with HNP and elevated magnetic properties of HNP@SWDC are apprehended via amide-imidol tautomerism associated nonconventional hydrogen bondings, disappearance of goethite specific -OH def. in HNP@SWDC, and VSM. The as-fabricated reusable HNP@SWDC is employed for removing methylene blue (MB) and rhodamine B (RhB). Chemisorption of RhB/MB in HNP@SWDC via ionic, electrostatic, and hydrogen bonding interactions alongside dimerization of dyes are realized by ultraviolet-visible, FTIR, and fluorescence studies; pseudosecond order fitting; and activation energies. The adsorption capacity = 46.98-56.14/22.89-27.57 mg g- 1 for RhB/MB is noted using 0.01 g HNP@SWDC within 5-20 ppm dyes and 288-318 K.

The intrinsically fluorescent highly hydrophilic multifunctional aliphatic terpolymer, maleic acid (MA)-co-2-(N-(hydroxymethyl)acrylamido)succinic acid (NHASA)-co-N-(hydroxymethyl)acrylamide (NHMA), that is, 1, was designed and synthesized via C–C/N–C-coupled in situ allocation of a fluorophore monomer, that is, NHASA, composed of amido and carboxylic acid functionalities in the polymerization of two nonemissive MA and NHMA. The scalable and reusable intrinsically fluorescent biocompatible 1 was suitable for sensing and high-performance adsorptive exclusion of Fe(III), along with the imaging of Madin–Darby canine kidney cells. The structure of 1, in situ fluorophore monomer, aggregation-induced enhanced emission, cell-imaging ability, and superadsorption mechanism were studied via microstructural analyses using 1H/13C NMR, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, atomic absorption spectroscopy, ultraviolet–visible spectroscopy, thermogravimetric analysis, dynamic light scattering, high-resolution transmission electron microscopy, solid-state fluorescence, fluorescence lifetime, and fluorescence imaging, along with measuring kinetics, isotherms, and thermodynamic parameters. The location, electronic structures, and geometries of the fluorophore and absorption and emission properties of 1 were investigated using density functional theory and natural transition orbital analyses. The limit of detection and the maximum adsorption capacity were 2.45 × 10–7 M and 542.81 mg g–1, respectively.

For initiating a prosperous cost-friendly waste management of small-scale industries, cow buffing dust (CBD), one of the abundantly available semisynthetic collagenic solid wastes, has been used as a nonsulfur cross-linker of natural rubber (NR) for fabricating an NRCBD-biocomposite superadsorbent. The as-prepared reusable biocomposite bearing variegated collagenic and noncollagenic N-donors, along with the O-donors, has been reported for ligand-selective preferential superadsorption from waste water. Thus, a CBD and NR-based scalable biocomposite bearing optimum cross-linking, excellent physicochemical properties, and reusability has been developed via systematic optimization of the torque and reaction time for cost-friendly adsorptive exclusion of dyes, such as 2,8-dimethyl-3,7-diamino-phenazine (i.e., safranine, SF) and (7-amino-8-phenoxazin-3-ylidene)-diethylazanium dichlorozinc dichloride (i.e., brilliant cresyl blue), BCB, and Hg(II). The CBD-aided curing of NR has been achieved through the formation of a cross-linked chromane-ring originated via reaction between the methylol-phenol ring of phenol-formaldehyde resin and isoprene unit of NR. The partial disappearance of unsaturation in cured-NRCBD, relative variation of crystallinity, surface properties, elevated thermal stabilities, and ligand-selective superadsorption have been studied by advanced microstructural analyses of unadsorbed and/or adsorbed NRCBD using Fourier transform infrared (FTIR), 13C nuclear magnetic resonance, ultraviolet-visible, and O 1s-/N 1s-/C 1s-/Hg 4f7/2,5/2-X-ray photoelectron spectroscopies, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, field emission scanning electron microscopy, energy-dispersive spectroscopy, and pHPZC. Response surface methodology-based optimization has been employed to attain the optimum potential of NRCBD, considering the interactive effects between pHi, temperature, and concentration of the dye. H-aggregate and time-dependent hypochromic effect has been observed during individual adsorption of dyes. Moreover, the prevalence of chemisorption via ionic interaction between NRCBD and SF, BCB, and Hg(II) has been realized by FTIR, fitting of kinetics data to the pseudosecond-order model, and measurement of activation energies. The Brunauer-Emmett-Teller and Langmuir isotherms fit the best to BCB and SF/Hg(II), respectively. Thermodynamically spontaneous chemisorption have shown the maximum adsorption capacities of 303.61, 46.14, and 166.46 mg g-1 for SF, BCB, and Hg(II), respectively, at low initial concentration of Hg(II)/dyes = 40 ppm, 303 K, and adsorbent dose = 0.01 g.

Goat buffing dust (GBD), an abundantly available collagenic-waste and crosslinked styrene butadiene rubber (SBR)-based scalable biocomposite showing excellent physicochemical properties and reusability was synthesized via systematic optimization of torque and time for exclusion(s) of dyes, such as safranine (SF) and brilliant cresyl blue (BCB), and Hg(II). The GBD-aided non-sulfur curing of SBR was attempted via chromane mechanism based reaction between resin components of GBD and pendant-C = C-of SBR. The decrease in the relative extent of unsaturation in cured-SBRGBD, alteration of crystallinity, surface properties, elevated thermal stabilities, and ligand-selective superadsorption were inferred through extensive microstructural analyses of unadsorbed and/or adsorbed SBRGBD using C-13 NMR, Ols-/N1s-/C1s-/Hg4f(7/2,5/2)-XPS, FTIR, UV-vis, TGA, XRD, FESEM, and EDX. Interactive effects between pHi, temperature, and concentration on adsorption capacities (ACs) were optimized through response surface methodology (RSM). The ionic interaction between SBRGBD and SF, BCB, and Hg(II) was understood through FTIR analyses, fitting of kinetics data to pseudosecond order model, and activation energies. BET and Langmuir isotherms were fitted the best to BCB and SF/Hg(II), respectively.

Unorthodox synthesis of natural polymer-g-terpolymer superadsorbent for exclusion of M(ii/iii).

Pectin-g-(sodium acrylate-co-3-(N-isopropylacrylamido) sodium propanoate-co-N-isopropylacrylamide) interpenetrating polymer networks (PANIPNs) were synthesized through systematic multistage optimization of equilibrium swelling ratio by response surface methodology for individual and/or synergistic removal(s) of cationic safranine (SF), anionic methyl orange, and M(II/III), such as Hg(II), Cd(II), and Cr(III). The relative effects of copolymer compositions on ligand-selective adsorption, strong/weak H-bonds, thermal stabilities, crystallinity, surface properties, swelling abilities, cross-link densities, network parameters, hydrophilic-hydrophobic characteristics, and adsorption capacities (ACs) were measured through extensive microstructural analyses of adsorbed and/or unadsorbed PANIPN41 and PANIPN21 bearing sodium acrylate and N-isopropylacrylamide (SA/NIPAm) in 4:1 and 2:1 ratios, respectively, using Fourier transform infrared, 1H and 13C NMR, X-ray photoelectron spectroscopy, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy, along with measuring lower critical solution temperature, % gel content (% GC), % -COOH, and pHPZC. Extensive UV-vis measurements were carried out at varying copolymer compositions, initial pH (pHi), and dyes, interpreted considering monomer-dimer and azonium-ammonium equilibrium of dye, dye-dye complexation, ligand-selective PANIPNs-dye adduct formation, π-π stacking interactions, and orientation effect of dyes. Thermodynamically feasible chemisorption processes showed the maximum ACs of 127.61, 96.78, 103.36, and 99.41 mg g-1 for SF, Hg(II), Cd(II), and Cr(III), respectively, under optimum conditions.

Herein, gum ghatti (GGTI)-g-[sodium acrylate (SA)-co-3-(N-(4-(4-methyl pentanoate))acrylamido)propanoate (NMPAP)-co-4-(acrylamido)-4-methyl pentanoate (AMP)-co-N-isopropylacrylamide (NIPA)] (i.e., GGTI-g-TetraP), a novel interpenetrating tetrapolymer network-based sustainable hydrogel, possessing extraordinary physicochemical properties and excellent recyclability, has been synthesized via grafting of GGTI and in situ strategic protrusion of NMPAP and AMP during the solution polymerization of SA and NIPA, through systematic multistage optimization of ingredients and temperature, for ligand-selective superadsorption of hazardous metal ions (M(II)), such as Sr(II), Hg(II), and Cu(II). The in situ allocation of NMPAP and AMP via N-H and C-H activations, grafting of GGTI into the SA-co-NMPAP-co-AMP-co-NIPA (TetraP) matrix, the effect of comonomer compositions on ligand-selective adsorption, crystallinity, thermal stabilities, surface properties, swellability, adsorption capacities (ACs), mechanical properties, and the superadsorption mechanism have been apprehended via extensive microstructural analyses of unloaded and/or loaded GGTI-g-TetraP1 and GGTI-g-TetraP2 bearing SA/NIPA in 8:1 and 2:1 ratios, respectively, using Fourier transform infrared (FTIR), 1H/13C/DEPT-135 NMR, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, field emission scanning electron microscopy, rheological analysis, and energy-dispersive X-ray spectrometry, along with measuring % gel content, pH at point of zero charge (pHPZC), and % graft ratio. The thermodynamically spontaneous chemisorption has been inferred from FTIR, XPS, fitting of kinetics data to pseudo-second-order model, and activation energies. The chemisorption data have exhibited excellent fitting to the Langmuir isotherm model. For Sr(II), Hg(II), and Cu(II), ACs were 1940.24/1748.36, 1759.50/1848.03, and 1903.64/1781.63 mg g-1, respectively, at 293 K, 0.02 g of GGTI-g-TetraP1/2, and initial concentration of M(II) = 500-1000 ppm.

Superadsorbent hydrogel with excellent physicochemical properties is used for mere/synergic chemisorption of dyes and M(ii).