- Publication Date:
- NSF-PAR ID:
- Journal Name:
- Nanoscale Advances
- Page Range or eLocation-ID:
- 2462 to 2470
- Sponsoring Org:
- National Science Foundation
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Degradable sugar-based magnetic hybrid nanoparticles for recovery of crude oil from aqueous environmentsIn this work, we designed and fabricated a nanoscopic sugar-based magnetic hybrid material that is capable of tackling environmental pollution posed by marine oil spills, while minimizing potential secondary problems that may occur from microplastic contamination. These readily-defined magnetic nanocomposites were constructed through co-assembly of magnetic iron oxide nanoparticles (MIONs) and a degradable amphiphilic polymer, poly(ethylene glycol)- b -dopamine-functionalized poly(ethyl propargyl glucose carbonate)- b -poly(ethyl glucose carbonate), PEG- b -PGC[(EPC-MPA)- co -(EPC-DOPA)]- b -PGC(EC), driven by supramolecular co-assembly in water with enhanced interactions provided via complexation between dopamine and MIONs. The composite nanoscopic assemblies possessed a pseudo -micellar structure, with MIONs trapped within the polymer framework. The triblock terpolymer was synthesized by sequential ring-opening polymerizations (ROPs) of two glucose-derived carbonate monomers, initiated by a PEG macroinitiator. Dopamine anchoring groups were subsequently installed by first introducing carboxylic acid groups using a thiol–yne click reaction, followed by amidation with dopamine. The resulting amphiphilic triblock terpolymers and MIONs were co-assembled to afford hybrid nanocomposites using solvent exchange processes from organic solvent to water. In combination with hydrophobic interactions, the linkage between dopamine and iron oxide stabilized the overall nanoscopic structure to allow for the establishment of a uniform globular morphology, whereas attempts atmore »
A Review on Electrospun Luminescent Nanofibers: Photoluminescence Characteristics and Potential Applications
Background: Photoluminescent materials have been used for diverse applications in thefields of science and engineering, such as optical storage, biological labeling, noninvasive imaging,solid-state lasers, light-emitting diodes, theranostics/theragnostics, up-conversion lasers, solar cells,spectrum modifiers, photodynamic therapy remote controllers, optical waveguide amplifiers andtemperature sensors. Nanosized luminescent materials could be ideal candidates in these applications.
Objective: This review is to present a brief overview of photoluminescent nanofibers obtainedthrough electrospinning and their emission characteristics.
Methods: To prepare bulk-scale nanosized materials efficiently and cost-effectively, electrospinningis a widely used technique. By the electrospinning method, a sufficiently high direct-current voltageis applied to a polymer solution or melt; and at a certain critical point when the electrostatic forceovercomes the surface tension, the droplet is stretched to form nanofibers. Polymer solutions or meltswith a high degree of molecular cohesion due to intermolecular interactions are the feedstock. Subsequentcalcination in air or specific gas may be required to remove the organic elements to obtainthe desired composition.
Results: The luminescent nanofibers are classified based on the composition, structure, and synthesismaterial. The photoluminescent emission characteristics of the nanofibers reveal intriguing featuressuch as polarized emission, energy transfer, fluorescent quenching, and sensing. An overview of theprocess, controlling parameters and techniques associated with electrospinning of organic, inorganicand composite nanofibers aremore »
Conclusion: The electrospinning process is a matured technique to produce nanofibers on a largescale. Organic nanofibers have exhibited superior fluorescent emissions for waveguides, LEDs andlasing devices, and inorganic nanofibers for high-end sensors, scintillators, and catalysts. Multifunctionalitiescan be achieved for photovoltaics, sensing, drug delivery, magnetism, catalysis, andso on. The potential of these nanofibers can be extended but not limited to smart clothing, tissueengineering, energy harvesting, energy storage, communication, safe data storage, etc. and it isanticipated that in the near future, luminescent nanofibers will find many more applications in diversescientific disciplines.
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Accelerated Reaction Rates within Self-Assembled Polymer Nanoreactors with Tunable Hydrophobic MicroenvironmentsPerforming reactions in the presence of self-assembled hierarchical structures of amphiphilic macromolecules can accelerate reactions while using water as the bulk solvent due to the hydrophobic effect. We leveraged non-covalent interactions to self-assemble filled-polymer micelle nanoreactors (NR) incorporating gold nanoparticle catalysts into various amphiphilic polymer nanostructures with comparable hydrodynamic nanoreactor size and gold concentration in the nanoreactor dispersion. We systematically studied the effect of the hydrophobic co-precipitant on self-assembly and catalytic performance. We observed that co-precipitants that interact with gold are beneficial for improving incorporation efficiency of the gold nanoparticles into the nanocomposite nanoreactor during self-assembly but decrease catalytic performance. Hierarchical assemblies with co-precipitants that leverage noncovalent interactions could enhance catalytic performance. For the co-precipitants that do not interact strongly with gold, the catalytic performance was strongly affected by the hydrophobic microenvironment of the co-precipitant. Specifically, the apparent reaction rate per surface area using castor oil (CO) was over 8-fold greater than polystyrene (750 g/mol, PS 750); the turnover frequency was higher than previously reported self-assembled polymer systems. The increase in apparent catalytic performance could be attributed to differences in reactant solubility rather than differences in mass transfer or intrinsic kinetics; higher reactant solubility enhances apparent reaction rates. Full conversionmore »
Synthesis and supramolecular organization of the iodide and triiodides of a polycyclic adamantane-based diammonium cation: the effects of hydrogen bonds and weak I⋯I interactionsA careful selection of organic and inorganic components enables the production of unusual structure types with promising practical properties by facile syntheses. In this paper, we describe novel supramolecular architectures comprising organic adamantane-like divalent building blocks and iodide or polyiodide anions. Highly acidic conditions facilitated the formation of a doubly protonated organic ligand out of 5,7-dimethyl-1,3-diazaadamantane that generates three different crystal structures with inorganic counterions. In these structures, cationic substructures are constructed by transforming neutral organic ligands into [(C 10 N 2 H 20 )I] + or [(C 10 N 2 H 20 )(H 2 O)] 2+ cations, which crystallize with charge-compensating iodine-based anions of different complexities. All three crystal structures are characterized by various noncovalent forces, ranging from strong (N)H⋯I, (O)H⋯I, and (N)H⋯O hydrogen bonds to secondary and weak I⋯I interactions. Raman and diffuse reflectance spectroscopy as well as DFT calculations were employed to describe the electronic structures and optical properties of new supramolecular architectures, with particular attention to the role of non-covalent interactions.