Soft particles in an electric field – a zero average contrast study

Nojd, Söfi; Hirst, Christopher; Obiols‐Rabasa, Marc; Schmitt, Julien; Rădulescu, Aurel; Mohanty, Priti S.; Schurtenberger, Peter

doi:10.1039/c9sm01208g

Cited by 9 publications

(6 citation statements)

References 23 publications

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“…In a follow-up, the same group has studied H-and D-microgels in presence of alternating electric fields, also under zero-average contrast [77]. The fuzzy sphere model successfully describes particle shapes for high and low fields, indicating that particles are not deformed by external electric forces.…”

Section: Crowded Microgel Systemsmentioning

confidence: 99%

Structure and Properties of Smart Micro‐ and Nanogels Determined by (Neutron) Scattering Methods

Oberdisse

Hellweg

2022

Smart Stimuli‐Responsive Polymers, Films, and Gels

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Meanwhile since more than three decades smart micro-and nanogels are studied and the number of publications in this area of research is steadily growing. This year to date (May 2021) already more than 400 articles were published on this topic. In the study of such colloidal gels the most important techniques besides microscopy are scattering techniques.In the present chapter an introduction to these non-destructive techniques and their application to smart micro-and nanogels will be given, and besides some fundamental works on this topic the most recent studies in this context will be discussed. We put a focus on multi-compartment and multi-1 stimuli responsive microgels and review time-resolved small-angle scattering experiments. In addition one section is devoted to the study of crowded microgel systems.

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Section: Crowded Microgel Systemsmentioning

confidence: 99%

Structure and Properties of Smart Micro‐ and Nanogels Determined by (Neutron) Scattering Methods

Oberdisse

Hellweg

2022

Smart Stimuli‐Responsive Polymers, Films, and Gels

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“…For example, ionic microgels that contain ionizable monomers, resulting for instance from the use of methacrylic acid (MAA) as comonomer, usually deswell more and at lower volume fractions ,, compared to the neutral microgels, such as the most common poly( N -isopropylacrylamide) (pNIPAM) microgels. ,,,, This has a profound effect on the macroscopic viscoelastic properties of the suspension ,, and can delay or even completely suppress the crystallization . Yet, other studies on slightly bigger ionic microgels report no such effects. − The disagreement between these studies can be attributed to the different environments in which the charged microgels are embedded that might lead to different osmotic pressure of the solution …”

Section: Introductionmentioning

confidence: 99%

Self-Healing of Charged Microgels in Neutral and Charged Environments

et al. 2023

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The softness of microgels depends on many aspects, such as particle characteristic lengths, sample concentration, chemical composition of the sample, and elastic moduli of the particle. Here, the response to crowding of ionic microgels is studied. Charged and uncharged ionic microgels are studied in concentrated suspensions of both neutral and ionic microgels with the same swollen size. The combination of small-angle X-ray and neutron scattering with contrast variation allows us to probe both the particle-to-particle arrangement and the response of individual ionic microgels to crowding. When the ionic microgels are uncharged, initial isotropic deswelling followed by faceting is observed. Therefore, the ionizable groups in the polymeric network do not affect the response of the ionic microgel to crowding, which is similar to what has been reported for neutral microgels. In contrast, the kind of microgels composing the matrix plays a key role once the ionic microgels are charged. If the matrix is composed of neutral microgels, a pronounced faceting and negligible deswelling is observed. When only charged ionic microgels are present in the suspension, isotropic deswelling without faceting is dominant.

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“…[4] Also the flow properties of colloidal suspensions can depend on the colloidal concentration. [5] Determination of the molar mass of soft nanoparticles can be achieved via static light scattering (SLS) with Zimm plot analysis [6][7][8][9] or via viscosimetry yielding the mass of a single microgel from which the molar mass is obtained by multiplication with Avogadro's number. [9][10][11] Analytical Ultracentrifugation is also able to yield the molar mass, requiring knowledge about further properties of the particles namely the partial specific volume which is the inverse of it's density and/or their anisotropy.…”

Section: Introductionmentioning

confidence: 99%

“…Fig 7. Zimm plot performed on SLS data of the microgel dispersion measured at the following concentrations: 0.05 g L −1 , 0.06 g L −1 , 0.07 g L −1 , 0.08 g L −1 and angles between 20 • and 40 • with 5 • steps and the interpolations to 0 • .…”

mentioning

confidence: 99%

A facile method to determine the molar mass of soft nanoparticles

Thomas,

Moritz,

Frédéric

et al. 2023

Preprint

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The determination of the molar mass of soft nanoparticles is essential to estimate their (molar) concentration in dispersions. Methods to measure this quantity are, however, challenging. We describe a facile way to determine the molar mass of (soft) nanoparticles via counting their amount per volume using a widefield fluorescence microscope. As model system we applied it to microgels, but it is applicable to other types of stainable nanoparticles. The method does not require covalent labeling or modification of the nanoparticles. The dispersion is simply mixed with a Nile Red solution in a defined ratio and measured in an optical fluorescence microscope to which most researchers in the field have access.

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Soft particles in an electric field – a zero average contrast study

Abstract: Small-angle neutron scattering experiments on microgels provide information about the response of the individual particles to an external electric field.

Cited by 9 publications

References 23 publications

Structure and Properties of Smart Micro‐ and Nanogels Determined by (Neutron) Scattering Methods

Structure and Properties of Smart Micro‐ and Nanogels Determined by (Neutron) Scattering Methods

Self-Healing of Charged Microgels in Neutral and Charged Environments

A facile method to determine the molar mass of soft nanoparticles

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