Thiol-functionalized silica colloids, grains, and membranes for irreversible adsorption of metal(oxide) nanoparticles

Claesson, E.M.; Philipse, Albert P.

doi:10.1016/j.colsurfa.2006.10.019

Cited by 52 publications

(40 citation statements)

References 27 publications

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“…A layer of dodecane thiol was first formed on the substrate to enhance particle attachment. Claesson and Philipse [32] have reported that the surface functionalization of silica using thiol allows the irreversible binding of metal oxide particles from a solution. A similar procedure was followed for the surface functionalization of the polyethylene substrate.…”

Section: Resultsmentioning

confidence: 99%

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Growth of ZnO nanowires on nonwoven polyethylene fibers

Baruah

Thanachayanont

Dutta

2008

Science and Technology of Advanced Materials

121

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We report the growth of ZnO nanowires on nonwoven polyethylene fibers using a simple hydrothermal method at a temperature below the boiling point of water. The ZnO nanowires were grown from seed ZnO nanoparticles affixed onto the fibers. The seed ZnO nanoparticles, with diameters of about 6-7 nm, were synthesized in isopropanol by reducing zinc acetate hydrate with sodium hydroxide. The growth process was carried out in a sealed chemical bath containing an equimolar solution of zinc nitrate hexahydrate and hexamethylene tetramine at a temperature of 95 • C over a period of up to 20 h. The thickness and length of the nanowires can be controlled by using different concentrations of the starting reactants and growth durations. A 0.5 mM chemical bath yielded nanowires with an average diameter of around 50 nm, while a 25 mM bath resulted in wires with a thickness of up to about 1 µm. The length of the wires depends both on the concentration of the precursor solution as well as the growth duration, and in 20 h, nanowires as long as 10 µm can be grown. The nonwoven mesh of polyethylene fibers covered with ZnO nanowires can be used for novel applications such as water treatment by degrading pollutants by photocatalysis. Photocatalysis tests carried out on standard test contaminants revealed that the polyethylene fibers with ZnO nanowires grown on them could accelerate the photocatalytic degradation process by a factor of 3.

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Section: Resultsmentioning

confidence: 99%

“…The substrate was treated with 1% dodecane thiol solution in ethanol and then heated at 100 • C for 15 min prior to the ZnO nanowire growth [32]. The substrates were seeded by dipping the thiolated substrates into a concentrated colloidal solution of ZnO nanoparticles in isopropanol for 15 min.…”

Section: Hydrothermal Growth Of Zno Nanowiresmentioning

confidence: 99%

Growth of ZnO nanowires on nonwoven polyethylene fibers

Baruah

Thanachayanont

Dutta

2008

Science and Technology of Advanced Materials

121

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“…This dialysis was needed for a surface functionalization, which cannot be done in water. 22 Since this dialysis transfer to ethanol does not affect the colloidal stability of the silica particles, 22 we can compare the results from DLS and SV AUC measurements on aqueous silica sols.…”

Section: Methodsmentioning

confidence: 99%

Model Independent Determination of Colloidal Silica Size Distributions via Analytical Ultracentrifugation

2008

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We report a method to determine the particle size distribution of small colloidal silica spheres via analytical ultracentrifugation and show that the average particle size, variance, standard deviation, and relative polydispersity can be obtained from a single sedimentation velocity (SV) analytical ultracentrifugation (AUC) experiment. The particle size distribution (psd) from the enhanced van HoldeWeischet (vHW) analysis accounts for the dynamic light scattering results quite well. In addition, the vHW psd equals the psd from a continuous distribution of sedimentation coefficients analysis where whole sedimentation velocity boundaries are fitted. The SV AUC interference optical data also yield the specific particle volume such that distributions of sedimentation coefficients for colloidal spheres can be converted directly to particle size distributions. Our results show that SV AUC experiments may yield a quantitative particle size distribution without a priori knowledge of the particle size and the shape of the size distribution.Synthetic macromolecules as well as colloids are always to a certain degree heterogeneous with respect to size and shape.For the size and shape determination, as well as the overall particle size distribution (psd), several techniques are available 1-3 such as transmission electron microscopy (TEM, or variations on this technique such as scanning electron microscopy and cryo-TEM) and atomic force microscopy (AFM). These microscopic techniques, except cryo-TEM, 4,5 do not image in situ. Drying of TEM samples may lead to particle shrinkage and distortion of particle structures, including aggregation due to capillary forces. Moreover, the electron beam may seriously damage the colloids via the melting and sintering of nanoparticles, as is the case for the small silica particles that are subject of the present study. Even if TEM images are fairly representative for the colloids in solution, many counts are needed for reliable statistics. For example, in the case of a polydispersity around 30%, typically at least 1000 counts are needed for a representative size distribution (see the case studies for various colloids in ref 1).Techniques that sample colloids in situ are static light scattering (SLS) and dynamic light scattering 6 (DLS). For sufficiently narrow size distributions, SLS data in the Guinier region can be analyzed with a momentum-expansion, to obtain an effective radius that is independent of the detailed shape of the distribution function. 1 For a broad size distribution, however, it is hardly possible to extract in any a priori fashion reliable distribution parameters from static light scattering profiles. DLS may be conducted on polydisperse colloids for which the particle shape is known, to obtain an apparent average particle size and standard deviation. The shape of the particle size distribution from DLS, however, may be highly questionable because of the ill-conditioned inversion problem encountered in DLS. 6 Since the scattered light intensity scales with the particle vo...

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“…As both ϕ-MSGNRs and β-MSGNRs possess regions of uncoated gold and one/two silicaencased end(s), two types of surfaces are available on these moieties for modification/functionalization; especially noteworthy in that both silica and gold can be readily modified for ligand conjugation via biocompatible silane and thiol functional groups, respectively. 31,32 Since the tips of GNRs are known to exhibit significant surface Raman enhancement and metal-enhanced fluorescence, ϕ-MSGNRs and β-MSGNRs also afford the opportunity to selectively modify Raman or fluorescent probes at the most efficacious sites.…”

Section: -25mentioning

confidence: 99%