SAXS studies on silica nanoparticle aggregation in a humid atmosphere

Partyka-Jankowska, E.; Leroch, Sabine; Akbarzadeh, Johanna; Pabisch, Silvia; Wendland, Martin; Peterlik, Herwig

doi:10.1007/s11051-014-2642-5

Cited by 6 publications

(5 citation statements)

References 24 publications

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“…Moreover, in order to further improve the accuracy of the fitting of the scattering curves, it was crucial to use a hard-sphere model as structure factor in most of the cases. The hard-sphere model is one of the most widely used model for aggregated systems [59]. This structure factor is described by two parameters: the hard-sphere radius R HS corresponding to the correlation distance of the particles within an aggregate and the mean hard-sphere volume η describing the degree of packing [60].…”

Section: Saxs Analysis Of the Sputtered Npsmentioning

confidence: 99%

Co-sputtering of gold and copper onto liquids: a route towards the production of porous gold nanoparticles

et al. 2020

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Effective methods for the synthesis of high-purity nanoparticles (NPs) have been extensively studied for a few decades. Among others, cold plasma-based sputtering metals onto a liquid substrate appears to be a very promising technique for the synthesis of high-purity NPs. The process enables the production of very small NPs without using any toxic reagents and complex chemical synthesis routes, and enables the synthesis of alloy NPs which can be the first step towards the formation of porous NPs. In this paper, the synthesis of gold-copper alloy NPs has been performed by co-sputtering gold and copper targets over pentaerythritol ethoxylate. The resulting solutions contain a mixture of gold, copper oxide, and alloy NPs having a radius of few angstroms. The annealing of these NPs, inside the solution, has been performed in order to increase their size and further induce the dealloying of the Au-Cu NPs. The resulting NPs exhibit either a nanoporous structure or are self-organized in an agglomerate of small NPs.

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Section: Saxs Analysis Of the Sputtered Npsmentioning

confidence: 99%

Co-sputtering of gold and copper onto liquids: a route towards the production of porous gold nanoparticles

et al. 2020

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“…Although SAXS has some drawbacks, such as a lower resolution compared to crystallography and elucidation mainly of the flexible regions of the molecules its advantage is that samples can be analyzed directly in the respective solutions [64] . For data evaluation, the Guinier concept of Radius of Gyration (R g ), a power law approximation of the scattering curve in the low q‐range with I(q)~q −n and the concept of pair distance distribution function p(r) were applied according to the literature [65–68] . The Radius of Gyration of MtL was found to be 5.6 nm in NaP and 5.5 nm in NaAc and the power law exponents were found to be 0.52 and 0.51 for the two systems, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…[64] For data evaluation, the Guinier concept of Radius of Gyration (R g ), a power law approximation of the scattering curve in the low qrange with I(q)~q À n and the concept of pair distance distribution function p(r) were applied according to the literature. [65][66][67][68] The Radius of Gyration of MtL was found to be 5.6 nm in NaP and 5.5 nm in NaAc and the power law exponents were found to be 0.52 and 0.51 for the two systems, respectively. These findings indicate that the size and conformation of MtL in the tested solutions are very similar.…”

mentioning

confidence: 95%

Effect of Salts on Laccase‐Catalyzed Polymerization of Lignosulfonate

Mayr,

Rennhofer,

Gille

et al. 2024

ChemSusChem

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Enzymatic polymerization of lignosulfonate (LS) has a high potential for various applications. Here, the effect of different ions in low concentrations on enzymatic polymerization of LS was investigated, including salt solutions consisting of mono‐ and dicarboxylic acids, sulfate, phosphate and chloride with sodium as counter ion. LS polymerization was followed by viscometry and size exclusion (SEC) chromatography. Interestingly, there was only a small effect of ions on the activity of the laccase on standard substrate ABTS, while the effect on polymerization of LS was substantially different. The presence of acetate led to a 39% higher degree of polymerization (DP) for LS. Small angle X‐ray scattering (SAXS) revealed that the structure of the enzyme was largely unaffected by the ions, while the determination of the zeta potential showed that those ions conveying higher negative surface charges onto LS particles showed lower DPs, than those not affecting the surface charge. Further, electron paramagnetic resonance (EPR) spectroscopy showed 5‐times higher intensity in phenoxyl radicals for the monovalent ions compared to the divalent ones. It was concluded that the DPs of LS could be tuned in the presence of certain ions, by facilitating the interaction between the laccase substrate‐binding site and the LS molecules.

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“…It is a great advantage of the SAXS method that colloidal systems can be investigated in real-time under their initial environment and nearly in any condition, which is an essential factor in colloidal stability research [18]. This method has been used for silica NP aggregating systems in a static state to observe the size and structural changes due to the changes in IS and humidity of the environment [22,23]. However, dynamical studies concerning the early stage of NP agglomeration remained open.…”

Section: Introductionmentioning

confidence: 99%

New approach for time-resolved and dynamic investigations on nanoparticles agglomeration

et al. 2020

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Nanoparticle (NP) colloidal stability plays a crucial role in biomedical application not only for human and environmental safety but also for NP efficiency and functionality. NP agglomeration is considered as a possible process in monodispersed NP colloidal solutions, which drastically affects colloidal stability. This process is triggered by changes in the physicochemical properties of the surrounding media, such as ionic strength (IS), pH value, or presence of biomolecules. Despite different available characterization methods for nanoparticles (NPs), there is a lack of information about the underlying mechanisms at the early stage of dynamic behaviors, namely changing in NP size distribution and structure while placing them from a stable colloidal solution to a new media like biological fluids. In this study, an advanced in situ approach is presented that combines small angle X-ray scattering (SAXS) and microfluidics, allowing label-free, direct, time-resolved, and dynamic observations of the early stage of NP interaction/agglomeration initiated by environmental changes. It is shown for silica NPs that the presence of protein in the media enormously accelerates the NP agglomeration process compared to respective changes in IS and pH. High IS results in a staring agglomeration process after 40 min, though, in case of protein presence in media, this time decreased enormously to 48 s. These time scales show that this method is sensitive and precise in depicting the dynamics of fast and slow NP interactions in colloidal conditions and therefore supports understanding the colloidal stability of NPs in various media concluding in safe and efficient NP designing for various applications.

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SAXS studies on silica nanoparticle aggregation in a humid atmosphere

Cited by 6 publications

References 24 publications

Co-sputtering of gold and copper onto liquids: a route towards the production of porous gold nanoparticles

Co-sputtering of gold and copper onto liquids: a route towards the production of porous gold nanoparticles

Effect of Salts on Laccase‐Catalyzed Polymerization of Lignosulfonate

New approach for time-resolved and dynamic investigations on nanoparticles agglomeration

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