Temperature induced phase separation of luminescent silica nanoparticles in Triton X-100 solutions

Mustafina, Asiya R.; Elistratova, Julia; Bochkova, Olga; Burilov, Vladimir; Fedorenko, Svetlana V.; Коновалов, А. И.; Soloveva, Svetlana Ye.

doi:10.1016/j.jcis.2010.11.050

Cited by 14 publications

(7 citation statements)

References 52 publications

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“…This is a striking example to show the potential significance of such displacement effects for the formulation of nanoparticle dispersions with nonionic surfactants. Related phenomena were reported recently by Mustafina et al 30…”

Section: Potential Application Relevancesupporting

confidence: 83%

Surfactant adsorption and aggregate structure at silica nanoparticles: Effects of particle size and surface modification

et al. 2012

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The influence of particle size and a surface modifier on the self-assembly of the nonionic surfactant C 12 E 5 at silica nanoparticles was studied by adsorption measurements and small-angle neutron scattering (SANS). Silica nanoparticles of diameter 13 to 43 nm were synthesized involving the basic amino acid lysine. A strong decrease of the limiting adsorption of C 12 E 5 with decreasing particle diameter was found. To unveil the role of lysine as a surface modifier for the observed size dependence of surfactant adsorption, the morphology of the surfactant aggregates assembled on pure siliceous nanoparticles (Ludox-TMA, 27 nm) and their evolution with increasing lysine concentration at a fixed surfactant-to-silica ratio was studied by SANS. In the absence of lysine, the surfactant forms surface micelles at silica particles. As the concentration of lysine is increased, a gradual transition from the surface micelles to detached wormlike micelles in the bulk solution is observed. The changes in surfactant aggregate morphology cause pronounced changes of the system properties, as is demonstrated by turbidity measurements as a function of temperature. These findings are discussed in terms of particle surface curvature and surfactant binding strength, which present new insight into the delicate balance between the two properties.

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Section: Potential Application Relevancesupporting

confidence: 83%

Surfactant adsorption and aggregate structure at silica nanoparticles: Effects of particle size and surface modification

et al. 2012

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Section: Potential Application Relevancesupporting

confidence: 82%

Surfactant Adsorption and Aggregate Structure at Silica Nanoparticles

Bharti

2014

Adsorption, Aggregation and Structure Formation in Systems of Charged Particles

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Surfactant adsorption onto colloidal particles is of eminent importance to technological processes in which colloidal stability or detergency plays a role [1][2][3][4][5]. Surfactant adsorption onto hydrophilic surfaces can be regarded as a surface aggregation process, reminiscent of micelle formation in solution [6][7][8][9][10][11][12][13][14]. When the anchoring of the surfactant heads to the surface is weak, as in the case of nonionic surfactants at oxide surfaces, the morphology of surface aggregates may depend both on the anchoring strength [15,16] and on the curvature of the adsorbing surface [17][18][19][20][21][22][23]. For instance, for the surfactant penta (ethyleneglycol) monododecylether (C 12 E 5 ) it was recently found that discrete surface micelles are formed on silica nanoparticles [19,21], although flat bilayers aggregates are preferred at planar silica surfaces [11,12]. At even weaker anchoring energies, surface micelles may be disfavored against micelles in solution, implying that little or no adsorption occurs, as in the case of dodecyl maltoside (β-C 12 G 2 ) at silica nanoparticles [19].Here, we study the influence of particle size and surface modification on the adsorption of the surfactant C 12 E 5 at silica nanoparticles. The particles were synthesized by a modified Stöber method [24] yielding particles of narrow size distribution down to the 10 to 50 nm size range which was of interest in this study. In this method, the basic amino acid lysine is used instead of ammonia as the catalyst for the hydrolysis of the silica precursor. For the resulting Lys-Sil particles [24] it was found that the adsorption isotherm of C 12 E 5 exhibits a pronounced dependence on particle size. To assess the influence of lysine on the surface energy and the adsorption of the surfactant at the silica particles we also investigated the adsorption of lysine on pure siliceous silica nanoparticles (Ludox-TMA) and

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“…Also, the binary mixtures of nonionic surfactant separate to two phases when exposed to heat-treatment. The temperature that phase separation occurs is called the cloud point (CP) temperature. , The micellar properties of nonionic surfactants, such as the critical micelle concentration (CMC), the micelle aggregation number, and liquid–liquid equilibrium, can be altered in the presence of solutes . In addition, alcohols hold a special place among additives to surfactant solutions due to implementation of their binary mixtures in order to produce microemulsions …”

Section: Introductionmentioning

confidence: 99%

Surfactant Binary Systems: Ab Initio Calculations, Preferential Solvation, and Investigation of Solvatochromic Parameters

et al. 2015

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Solvatochromic UV−vis shifts of three probes 4-nitroaniline, 4-nitroanisol, and Reichardt's dye in binary mixtures of polyethylene glycol p-(1,1,3,3tetramethylbutyl)-phenyl ether (Triton X-100 or TX-100) with methanol, ethanol, 1propanol, and water have been investigated at 298 K. Structural and intermolecular interactions of solvatochromic probes were determined in these systems. Solvatochromic parameters, including normalized polarity (E T N ), dipolarity-polarizability (π*), hydrogenbond donor (α), and hydrogen-bond acceptor (β) abilities, were measured at a wide range of mole fraction (0 ≤ X ≤ 1) with 0.1 increment. Interestingly, a similar behavior of E T N and α is observed in alcohols/TX-100 mixtures. The E T N parameters obtained from absorbance of Reichardt's dye within various mixtures of surfactant were observed to be lower than predicted values from ideal additive behavior. A negative deviation from ideality is shown by E T N parameter in all alcohols/TX-100 mixtures, while a fluctuated behavior for other probes can be seen. The optimized geometries exhibit that the hydroxyl (−OH) group on the side chain of TX-100 significantly affects the arrangement of the selected solvents around TX-100. All binary systems show complex behavior for chosen probes. The results demonstrate that 4-nitroanisole and Reichardt's dye have stronger interactions with binary mixtures of alcohols/TX-100 systems. Synergistic solvation behavior for water/TX-100 was observed. Preferential solvation model was applied for the first time in the surfactant binary mixtures and from this model information solute−solvent and solvent−solvent interactions were interpreted. Preferential solvation (specific solute−solvent interactions) or the solvent−solvent interaction is the reason for deviation from ideal behavior of probes. As a main result, alkyl chain length of alcoholic solvents does not have impressive effects on predicted trends of solvatochromic parameters. Ab initio calculations of solvents/TX-100 mixtures demonstrate the following trend for magnitude order of interactions: water > methanol > ethanol >1-propanol. Electrostatic potential map is another confident evidence for predicted order.

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Temperature induced phase separation of luminescent silica nanoparticles in Triton X-100 solutions

Cited by 14 publications

References 52 publications

Surfactant adsorption and aggregate structure at silica nanoparticles: Effects of particle size and surface modification

Surfactant adsorption and aggregate structure at silica nanoparticles: Effects of particle size and surface modification

Surfactant Adsorption and Aggregate Structure at Silica Nanoparticles

Surfactant Binary Systems: Ab Initio Calculations, Preferential Solvation, and Investigation of Solvatochromic Parameters

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