1,721,553 research outputs found
Chirally enhanced solubilization through perylene-based surfactant
No full textRecently we introduced a rationally designed surfactant which forms energy transfer complexes with carbon nanotubes. We investigate the chiral selectivity of this compound, a perylene derived surfactant, through photoluminescence (PL) measurements, and find a strong enhancement of the luminescence intensity for one particular group of chiralities. The effect is striking, with luminescence increases of several hundred percent.
Chiral selectivity of the investigated surfactant compound as compared to solubilization through sodium cholate (SC). Small numbers indicate chirality, large numbers laola family
Functional Surfactants for Carbon Nanotubes: Effects of Design
No full textSurfactants are needed to create stable suspensions of carbon nanotubes. Increasingly, these surfactants are given additional functionalities, resulting in bigger and more complex molecules with several subunits. We investigate the effect of assembly of these subunits for a class of perylene-based functional surfactants. The subunits that all surfactants are based on are a perylene core, hydrophilic polyglycerol dendrons, and alkyl chains of different orientations and lengths. The assembly of these subunits affects both the molecules' performance as a surfactant and the efficiency of the energy-transfer complexes formed by the nanotube and surfactant through a π–π stacking mechanism. This results in a best practice guide for designing functional surfactants with π–π stacking cores, and affords more general insights that are applicable to non π–π stacking systems as well
Energy Transfer in Nanotube-Perylene Complexes
No full textA functional surfactant designed to solubilize and individualize nanotubes efficiently in aqueous media and to form energy transfer complexes with the carbon nanotubes through π–π stacking is presented. Upon excitation of the adsorbed perylene unit an emission from the nanotubes is observed that indicates a successful excitation transfer. The efficiency of the indirect excitation via the adsorbant is of the same order of magnitude as the direct excitation of the nanotubes. Under optimized preparation conditions the pH independent perylene-imido-diester compound isolates and solubilizes carbon nanotubes in biocompatible aqueous environments without additional surfactants. The resulting solutions are stable over many months
sj-docx-1-asn-10.1177_17590914211073381 - Supplemental material for Optimization of Long-Term Human iPSC-Derived Spinal Motor Neuron Culture Using a Dendritic Polyglycerol Amine-Based Substrate
No full textSupplemental material, sj-docx-1-asn-10.1177_17590914211073381 for Optimization of Long-Term Human iPSC-Derived Spinal Motor Neuron Culture Using a Dendritic Polyglycerol Amine-Based Substrate by Louise Thiry, Jean-Pierre Clément, Rainer Haag, Timothy E Kennedy and Stefano Stifani in ASN Neuro</p
Excitation characteristics of different energy transfer in nanotube-perylene complexes
Full text linkWe report the properties of perylene-nanotube complexes that form efficient energy transfer systems. Most perylene-derivatives yield similar ratios between transfer and direct luminescence (0.66 ± 0.04). The photoluminescence spectra of the free compounds and the transfer complex are similar indicating that perylene and nanotubes act as separate systems. A further increase in interaction yields 40% higher transfer rates and luminescence excitation spectra that indicate a change in stacking of the perylene on the nanotube wall. All measurements are consistent with a transfer mechanism based on a dipole-dipole interaction at a distance much smaller than the Förster radius
Selective interaction between nanotubes and perylene-based surfactant
No full textWe recently reported a significant deviation in the photoluminescence intensities of HiPco nanotubes solubilized with a perylene-based surfactant, C16, compared to bile salt surfactants. For C16, the photoluminescence emission of chiralities (9,5), (10,3), and (11,1) is enhanced by up to 430%. Resonant Raman spectroscopy is less sensitive to bundling state and also yields disparate chirality intensity ratios: The (11,0) zigzag tube signal increases by 100% compared to (8,6), (9,4), and (10,2) after suspension with C16. We also report the change in photoluminescence intensity distribution after the swelling of bile salt suspended nanotubes with a series of small organic chromophores in DCM. These changes are attributed to chromophore-induced surfactant reorganization, resulting in better nanotube individualization. The chirality for which the PL intensity is most enhanced is (11,1) for all chromophores, a chirality also increased by 300% in the C16-solubilized sample. Conjointly, these measurements indicate that both preferential solubilization and enhanced debundling contribute to the PL intensity distribution in the C16-solubilized nanotube sample. This has wide ranging implications for the design of chirally selective surfactants and the demonstration of their selectivity, which is typically only shown through luminescence measurements
Interaction between single-walled carbon nanotubes and alkyl-polyglycerol derivatives
No full textWe use three alkyl-polyglycerol derivatives to suspend singlewalled
carbon nanotubes. The molecules differ by the aromatic
moieties between the alkyl tail and the polyglycerol head. The
suspended nanotubes are analysed by photoluminescence
spectroscopy. We observe a dependence of the luminescence
intensity and hence nanotube abundance on the aromatic
moieties. Interestingly, the strength of interaction depends on
the nanotube families
Amphiphile replacement on carbon nanotube surfaces: Effect of aromatic groups on the interaction strength
No full textCarbon nanotubes (CNTs) were solubilized using akyl/polyglycerol amphiphiles. Similar cosurfactants, bearing different aromatic moieties between head and tail, were added to these samples. The interaction strength between these amphiphiles and CNTs changes depending on the inserted aromatic moieties. The insertion of a phenyl ring allows the amphiphile to replace the starting one indicating a higher interaction strength, while the insertion of a triazol pentagon does not, suggesting that the interaction strength is lower. The replacement was monitored via PLE mapping
Dispersion of carbon nanotubes using an azobenzene derivative
No full textAqueous dispersions of carbon nanotubes (CNTs) were
obtained by noncovalent adsorption of an azobenzene derivative
carrying polyglycerol dendric structures. UV/Vis absorption
spectra and photoluminescence maps were recorded to
confirm successful nanotube debundling and suspension.
Comparison to dispersion of nanotubes using sodium dodecyl
sulfate (SDS) revealed shifts of the nanotube E22 excitation
peaks from 28 to 67 meV as well as shifts from 21 to 37 meV of
the E11 emission peaks
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