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Main Title: Surfactant adsorption and aggregate structure at silica nanoparticles: Effects of particle size and surface modification
Author(s): Bharti, Bhuvnesh
Meissner, Jens
Gasser, Urs
Findenegg, Gerhard H.
Type: Article
Language Code: en
Abstract: The influence of particle size and a surface modifier on the self-assembly of the nonionic surfactant C12E5 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 C12E5 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.
Issue Date: 2012
Date Available: 29-Jun-2016
DDC Class: 530 Physik
Sponsor/Funder: EC/FP7/226507/EU/Integrated Infrastructure Initiative for Neutron Scattering and Muon Spectroscopy/NMI3
DFG, GRK 1524, Self-Assembled Soft-Matter Nanostructures at Interfaces
Journal Title: Soft matter
Publisher: Royal Society of Chemistry
Publisher Place: Cambridge
Volume: 8
Issue: 24
Publisher DOI: 10.1039/c2sm25648g
Page Start: 6573
Page End: 6581
EISSN: 1744-6848
ISSN: 1744-683X
Notes: Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.
Appears in Collections:Inst. Chemie » Publications

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