Role of attached polymer chains on the vibrational relaxation of a<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi mathvariant="normal">C</mml:mi><mml:mn>60</mml:mn></mml:msub></mml:math>fullerene in aqueous solution

Kim, Hojin; Bedrov, Dmitry; Smith, Grant D.; Shenogin, Sergei; Keblinski, Pawel

doi:10.1103/physrevb.72.085454

Cited by 11 publications

(18 citation statements)

References 28 publications

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“…Preparing aqueous solutions of fullerenes has been a great challenge for biochemical, biophysical, and biological applications of these molecules [1][2][3][4] since the discovery of C 60 20 years ago [5]. Due to the hydrophobic interactions of fullerenes in aqueous environments [6], usually functionalized species are employed to obtain water-soluble forms [1,3]. Also, pristine fullerenes have been solubilized in aqueous acids by ultrasonic method [7].…”

Section: Introductionmentioning

confidence: 99%

Theoretical calculations of the structure and UV–vis absorption spectra of hydrated C60 fullerene

Rivelino

Maniero

Prudente

et al. 2006

Carbon

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A combined Monte Carlo simulation with semiempirical quantum mechanics calculations has been performed to investigate the structure of hydrated fullerene (C 60 HyFn) and the influence of hydration on its UV-vis spectra. The statistical information of the C 60 fullerene aqueous solution (C 60 FAS) is obtained from NPT ensemble including one C 60 fullerene immerses in 898 water molecules. To obtain an efficient ensemble average, the auto-correlation function of the energy has been calculated. The analyzed center-of-mass pair-wise radial distribution function indicates that, on average, there are 65 and 151 water molecules around the first and second hydration shells, respectively, of a single C 60 molecule. To calculate the average UV-vis transition energies of C 60 HyFn, only the statistically uncorrelated configurations are used in the quantum mechanical calculations (INDO/CIS). These involve hundreds of supramolecular structures containing one C 60 fullerene surrounded by the first hydration shell. The calculated average transitions at 268 and 350 nm are in very good agreement with the experimental prediction.

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Section: Introductionmentioning

confidence: 99%

Theoretical calculations of the structure and UV–vis absorption spectra of hydrated C60 fullerene

Rivelino

Maniero

Prudente

et al. 2006

Carbon

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“…Alignment effects for amorphous nanoparticles have also been studied [12]. Kim et al [13] used molecular dynamics (MD) simulations to study the relaxation of a fullerene molecule coated with poly(ethylene oxide) (PEO). Other simulations have either relied upon implicit solvents [14] or studied nanoparticles in a vacuum [15,16].…”

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confidence: 99%

Forces between functionalized silica nanoparticles in solution

et al. 2009

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To prevent the flocculation and phase separation of nanoparticles in solution, nanoparticles are often functionalized with short chain surfactants. Here we present fully-atomistic molecular dynamics simulations which characterize how these functional coatings affect the interactions between nanoparticles and with the surrounding solvent. For 5 nm diameter silica nanoparticles coated with poly(ethylene oxide) (PEO) oligomers in water, we determined the hydrodynamic drag on two approaching nanoparticles moving through solvent and on a single nanoparticle as it approaches a planar surface. In most circumstances, macroscale fluid theory accurately predicts the drag on these nano-scale particles. Good agreement is seen with Brenner's analytical solutions for wall separations larger than the soft nanoparticle radius. For two approaching coated nanoparticles, the solvent-mediated (velocity-independent) and lubrication (velocity-dependent) forces are purely repulsive and do not exhibit force oscillations that are typical of uncoated rigid spheres.There is increasing interest in using nanoparticles in commercial and industrial applications. However, effective processing of nanoparticles requires that they do not aggregate and often involves solvation in a fluid. Functionalizing the nanoparticles accomplishes both goals. The behavior of functionalized nanoparticles depends strongly on the attached groups. The behavior of bare, nonfunctionalized nanoparticles has been studied via experiments, theory, and simulation, as have the interactions of polymer-grafted surfaces [1,2,3,4]. The hydrodynamic and nanoparticle-nanoparticle interactions involving small functionalized nanoparticles, however, are harder to characterize. Experimentally, it is difficult to manipulate and measure forces on individual nanoparticles smaller than ∼ 100 nm. Theoretical treatments are challenging because the coatings are relatively short, while the particles themselves are outside the large radius of curvature limit. Numerical simulations of discrete solvent effects on nanoparticles have been impractical until now because of the large systems required to avoid significant finite-size effects due to the long-range hydrodynamic interactions. For single-particle diffusion, these corrections have been shown [5,6] to scale as R/L where R is the particle radius and L is the simulation cell length.Recent studies have computed the potential of mean force for bare silica nanoparticles in an aqueous medium, with and without electrolytes present [7]. Forces between bare colloidal nanoparticles have also been studied in LennardJones fluids and in n-decane [8]. Hydrodynamic drag influenced by approach to a plane surface has been studied theoretically [9] and compared to simulations for rigid spheres [10,11]. Alignment effects for amorphous nanoparticles have also been studied [12]. Kim et al.[13] used molecular dynamics (MD) simulations to study the relaxation of a fullerene molecule coated with poly(ethylene oxide) (PEO). Other simulations have either relied u...

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“…Contrastingly, as mentioned above, we have demonstrated diffusive transport across the molecular layers where the intrinsic vibrational properties of the molecule provide a distinct channel for heat conduction . In this regard, studies of mode coupling due to chemical moieties at fullerene derivative/liquid interfaces have been limited to simulations. , Due to the results of these simulations , and our previous work, we expect thermal transport in fullerene derivatives to be diffusive ( i . e ., the vibrational modes in the functional group are thermally activated) and hypothesize that h K is dictated by the presence of specific low-frequency vibrational modes.…”

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confidence: 59%

“…To better understand these thermal transport pathways, the relaxation of photoexcited fullerenes and the resulting characterization of these relaxation processes and thermal transport properties have been the focus of considerable research in the past decade. ,,− The thermal transport processes in fullerene derivatives, which here we define as C 60 with molecular functional groups, have received far less attention. The vibrations contributing to the thermal transport properties of fullerenes consist of predominantly localized modes (commonly referred to as Einstein oscillations), which have been ascribed as the primary mechanism responsible for the ultralow thermal conductivities observed in fullerene and fullerene-derivative thin films. − …”

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Molecular Tuning of the Vibrational Thermal Transport Mechanisms in Fullerene Derivative Solutions

Szwejkowski¹,

Giri²,

Warzoha

et al. 2017

ACS Nano

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Control over the thermal conductance from excited molecules into an external environment is essential for the development of customized photothermal therapies and chemical processes. This control could be achieved through molecule tuning of the chemical moieties in fullerene derivatives. For example, the thermal transport properties in the fullerene derivatives indene-C monoadduct (ICMA), indene-C bisadduct (ICBA), [6,6]-phenyl C butyric acid methyl ester (PCBM), [6,6]-phenyl C butyric acid butyl ester (PCBB), and [6,6]-phenyl C butyric acid octyl ester (PCBO) could be tuned by choosing a functional group such that its intrinsic vibrational density of states bridge that of the parent molecule and a liquid. However, this effect has never been experimentally realized for molecular interfaces in liquid suspensions. Using the pump-probe technique time domain thermotransmittance, we measure the vibrational relaxation times of photoexcited fullerene derivatives in solutions and calculate an effective thermal boundary conductance from the opto-thermally excited molecule into the liquid. We relate the thermal boundary conductance to the vibrational modes of the functional groups using density of states calculations from molecular dynamics. Our findings indicate that the attachment of an ester group to a C molecule, such as in PCBM, PCBB, and PCBO, provides low-frequency modes which facilitate thermal coupling with the liquid. This offers a channel for heat flow in addition to direct coupling between the buckyball and the liquid. In contrast, the attachment of indene rings to C does not supply the same low-frequency modes and, thus, does not generate the same enhancement in thermal boundary conductance. Understanding how chemical functionalization of C affects the vibrational thermal transport in molecule/liquid systems allows the thermal boundary conductance to be manipulated and adapted for medical and chemical applications.

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Role of attached polymer chains on the vibrational relaxation of aC60fullerene in aqueous solution

Cited by 11 publications

References 28 publications

Theoretical calculations of the structure and UV–vis absorption spectra of hydrated C60 fullerene

Theoretical calculations of the structure and UV–vis absorption spectra of hydrated C60 fullerene

Forces between functionalized silica nanoparticles in solution

Molecular Tuning of the Vibrational Thermal Transport Mechanisms in Fullerene Derivative Solutions

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