Abstract:Multistimuli-responsive hyperbranched poly(ether amine)s (hPEAs) were successfully synthesized through nucleophilic addition/ring-opening reaction of commercial diglycidyl ether and amine via one-pot synthesis. In aqueous solution, these hPEAs exhibited very sharp response to temperature, pH, and ionic strength, with well-tunable cloud point (CP). Through changing the poly(ethylene oxide) (PEO) chain content of hPEAs, pH, and ionic strength, the CP could be adjustable from 35 to 100 C, and increased with the i… Show more
“…In addition, the characteristic peaks at 2.2–3.1 ppm and 3.2–4.2 ppm corresponded to the signal from -CH 2 - and -CH- connected to nitrogen and oxygen atoms, respectively. These results indicated the successful synthesis of WHPA according to the literature 31 .Figure 1The preparation process of WHPA-OMCNT nanoadsorbent.Figure 2Characterization of as-prepared adsorbent: 1 H NMR spectrum of WHPA in CDCl 3 ( A ); FTIR spectra ( B ) and TGA analysis ( C ) of OMCNT, WHPA and WHPA-OMCNT; Zeta potential of WHPA-OMCNT ( D ); photographs for the dispersion status of OMCNT ( E ) and WHPA-OMCNT ( F ) in water settled for 3 h and two months, respectively; SEM images of OMCNT ( G,H ) and WHPA-OMCNT ( I,J ); TEM images of OMCNT ( K,L ) and WHPA-OMCNT ( M,N ); 3D models of MB, MG and MV molecules ( O ).
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Water-soluble hyperbranched polyamine functionalized multiwalled carbon nanotubes nanocomposite (WHPA-OMCNT) was successfully prepared and applied to water remediation in this paper. WHPA-OMCNT was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), zeta potential, scanning electron microscopy (SEM) and transmission electron microscope (TEM) analyses. WHPA-OMCNT exhibited excellent adsorption performance for removal of organic dyes e.g., methylene blue (MB), malachite green (MG) and methyl violet (MV). The equilibrium adsorption capacity was 800.0 mg g−1 for MB, 840.3 mg g−1 for MG and 970.9 mg g−1 for MV under the optimal conditions. The pseudo-second order equation and the Langmuir model exhibited good correlation with the adsorption kinetic and isotherm data for all three pollutants, respectively. The thermodynamic results (ΔG < 0, ΔH < 0, ΔS < 0) implied that the adsorption process of MB, MG and MV was feasible, exothermic and spontaneous in nature. A possible adsorption mechanism has been proposed, where H-bonding, electrostatic attraction and π-π stacking interactions dominated the adsorption of the organic dyes. In addition, the excellent reproducibility endowed WHPA-OMCNT with the potential for application in water treatment.
“…In addition, the characteristic peaks at 2.2–3.1 ppm and 3.2–4.2 ppm corresponded to the signal from -CH 2 - and -CH- connected to nitrogen and oxygen atoms, respectively. These results indicated the successful synthesis of WHPA according to the literature 31 .Figure 1The preparation process of WHPA-OMCNT nanoadsorbent.Figure 2Characterization of as-prepared adsorbent: 1 H NMR spectrum of WHPA in CDCl 3 ( A ); FTIR spectra ( B ) and TGA analysis ( C ) of OMCNT, WHPA and WHPA-OMCNT; Zeta potential of WHPA-OMCNT ( D ); photographs for the dispersion status of OMCNT ( E ) and WHPA-OMCNT ( F ) in water settled for 3 h and two months, respectively; SEM images of OMCNT ( G,H ) and WHPA-OMCNT ( I,J ); TEM images of OMCNT ( K,L ) and WHPA-OMCNT ( M,N ); 3D models of MB, MG and MV molecules ( O ).
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Water-soluble hyperbranched polyamine functionalized multiwalled carbon nanotubes nanocomposite (WHPA-OMCNT) was successfully prepared and applied to water remediation in this paper. WHPA-OMCNT was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), zeta potential, scanning electron microscopy (SEM) and transmission electron microscope (TEM) analyses. WHPA-OMCNT exhibited excellent adsorption performance for removal of organic dyes e.g., methylene blue (MB), malachite green (MG) and methyl violet (MV). The equilibrium adsorption capacity was 800.0 mg g−1 for MB, 840.3 mg g−1 for MG and 970.9 mg g−1 for MV under the optimal conditions. The pseudo-second order equation and the Langmuir model exhibited good correlation with the adsorption kinetic and isotherm data for all three pollutants, respectively. The thermodynamic results (ΔG < 0, ΔH < 0, ΔS < 0) implied that the adsorption process of MB, MG and MV was feasible, exothermic and spontaneous in nature. A possible adsorption mechanism has been proposed, where H-bonding, electrostatic attraction and π-π stacking interactions dominated the adsorption of the organic dyes. In addition, the excellent reproducibility endowed WHPA-OMCNT with the potential for application in water treatment.
“…12 Moreover, with the increasing pH value from 7.0 to 9.0, the z-average diameter of the microgel increased dramatically from 750 to 1280 nm, which should be ascribed to ionization of carboxyl groups at higher pH. 12 Moreover, with the increasing pH value from 7.0 to 9.0, the z-average diameter of the microgel increased dramatically from 750 to 1280 nm, which should be ascribed to ionization of carboxyl groups at higher pH.…”
We here demonstrated a novel strategy of one-pot approach to synthesize hyperbranched poly (thiol-ether amine) (hPtEA) through sequential "thiol-ene" and "epoxy-amine" click reaction, both of which were well traced by the in-situ 1 H-NMR spectra. The obtained hPtEA with high branching degree (DB) of 0.83 and molecular weight (M n ) of 8.6Х10 3 was comprised of large amount of hydroxyl groups in the backbone and amino groups in the periphery. Moreover, hPtEA could be further functionalized orthogonally due to the difference in the chemistry between hydroxyl and amino group. So fluorescent anthracene (AN) and carboxyl (SA) groups were introduced to the periphery and backbone of hPtEA, respectively, and the amphiphilic and zwitterionic hPtEA (SA-hPtEA-AN) were obtained. The resulting SA-hPtEA-AN could self-assemble into microsphere in aqueous solution with uniformed size of 750 nm in diameter, which was further cross-linked through photo-dimerization of AN groups. The microgel of SA-hPtEA-AN is fluorescent and responsive to environmental stimulus such as temperature and pH, and can be used in the encapsulation and controlled release of guest molecules. In addition, the controlled release of guest molecules from microgel of SA-hPtEA-AN can be monitored by its fluorescence change.
“…The above polymers could all self‐assemble into micelles that were multi‐stimuli responsive to temperature, pH, and ionic strength. In addition, PEA with hyperbranched structure was also synthesized 129. Nanoparticles based on the amphiphilic azobenzene‐containing hyperbranched PEA were prepared, which could exhibit sensitivity not only to temperature, pH, and ionic strength but also to UV light by incorporating the light‐sensitive azobenzene units into the hyperbranched polymer 130.…”
Stimuli-responsive polymers have received tremendous attention from scientists and engineers for several decades due to the wide applications of these smart materials in biotechnology and nanotechnology. Driven by the complex functions of living systems, multi-stimuli-responsive polymer materials have been designed and developed in recent years. Compared with conventional single- or dual-stimuli-based polymer materials, multi-stimuli-responsive polymer materials would be more intriguing since more functions and finer modulations can be achieved through more parameters. This critical review highlights the recent advances in this area and focuses on three types of multi-stimuli-responsive polymer materials, namely, multi-stimuli-responsive particles (micelles, micro/nanogels, vesicles, and hybrid particles), multi-stimuli-responsive films (polymer brushes, layer-by-layer polymer films, and porous membranes), and multi-stimuli-responsive bulk gels (hydrogels, organogels, and metallogels) from recent publications. Various stimuli, such as light, temperature, pH, reduction/oxidation, enzymes, ions, glucose, ultrasound, magnetic fields, mechanical stress, solvent, voltage, and electrochemistry, have been combined to switch the functions of polymers. The polymer design, preparation, and function of multi-stimuli-responsive particles, films, and bulk gels are comprehensively discussed here.
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